JPH0452429Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a boiling cooling system for an internal combustion engine that utilizes the boiling condensation cycle of a refrigerant, especially a boiling cooling system for a slant-type internal combustion engine that is mounted in a slanted state in an automobile or the like. Regarding.

Prior Art The present applicant has formed a closed-loop refrigerant circulation system mainly consisting of a water jacket of an internal combustion engine, a condenser, and a refrigerant supply pump, and stores liquid phase refrigerant up to a predetermined level in the water jacket. ,
The boiling vaporization cools each part of the engine, and the refrigerant vapor generated in the water jacket is led to the condenser and condensed, and then the water is re-energized by intermittent operation of the refrigerant supply pump based on detection by the liquid level sensor. Various boiling cooling devices have been proposed that supply water to a jacket (for example, JP-A-60-36712, JP-A-60-36715, etc.). In this evaporative cooling device, the water jacket includes a cylinder head side water jacket formed on the cylinder head so as to cover the combustion chamber wall, etc., and a cylinder block side water jacket formed on the cylinder block so as to surround the cylinder. The two are connected through a plurality of communication holes to form a substantially integrated structure. The liquid phase refrigerant (e.g. ethylene glycol aqueous solution, etc.) is usually stored up to the middle height of the water jacket on the cylinder head side so that high heat load parts such as the combustion chamber walls are submerged in the liquid phase refrigerant. The refrigerant vapor is extracted from the top of the cylinder head.

Here, the vapor space formed above the refrigerant liquid level in the water jacket is designed to suppress the vapor flow rate and reduce the refrigerant droplets carried out to the condenser side along with the vapor flow. It is necessary to ensure the size.

By the way, a so-called slant-type internal combustion engine, in which the center axis of each cylinder is inclined with respect to the vertical line, is known as an internal combustion engine for automobiles, as shown in, for example, Japanese Utility Model Application Publication No. 106323/1983. ing. This slant-type internal combustion engine has the advantage of being able to reduce the height from the crankshaft to the top of the engine, for example in cab-over type cars that require sufficient space above the internal combustion engine, and the height of the car body hood. Applicable when setting it low. As shown in the above-mentioned publication, this slant-type internal combustion engine is often constructed in a slant state in which the exhaust valve seat of the cylinder head is on the lower side and the intake valve seat is on the upper side.

Problems to be solved by the invention If the boiling cooling device described above is applied to a slant-type internal combustion engine as described above, the refrigerant liquid level in the water jacket will naturally be a horizontal surface, so It is in a state of inclination with respect to the central axis.

Therefore, if the slant angle is quite large,
On the high intake side, the refrigerant liquid level is located below the upper end surface of the cylinder block, and the upper end of the cylinder on the intake side is exposed to the vapor space. As a result, the upper end of the cylinder, which is a portion subject to a high heat load, may suffer from insufficient cooling, which may cause scuffing of the piston ring.

Note that if the slant angle is large and the refrigerant level is set high so that the cylinder is completely submerged in the liquid refrigerant, it may not be possible to secure enough vapor space in the upper part, or the cylinder head may become too tight. It becomes a large one.

Means to Solve the Problem Therefore, in this invention, the central axis of each cylinder is arranged at an angle with respect to the vertical line so that the exhaust valve seat of the cylinder head is on the lower side and the intake valve seat is on the upper side. In a boiling cooling system for an internal combustion engine, which cools various parts by boiling and vaporizing the liquid phase refrigerant stored up to a predetermined level in the water jacket, the liquid phase refrigerant is fed from the condenser by the refrigerant supply pump. A refrigerant supply port is formed at a relatively lower portion of the water jacket on the cylinder block side, and a communication hole that communicates the water jacket on the cylinder block side and the water jacket on the cylinder head side is formed only on the intake side, which is at a higher level. Moreover, a liquid level sensor for detecting the height of the refrigerant liquid level is disposed in the water jacket on the cylinder head side.

Operation In the above configuration, the liquid phase refrigerant fed from the condenser into the water jacket by the refrigerant supply pump flows into the lower part of the water jacket on the cylinder block side through the refrigerant supply port,
From there, it flows to the upper part of the intake side of the water jacket on the cylinder block side, and then flows into the water jacket on the cylinder head side through a communication hole provided only on the intake side. Therefore, even if the set level specified by the liquid level sensor is lower than the upper end of the intake side of the water jacket on the cylinder block side, the water jacket on the cylinder block side is always filled with liquid phase refrigerant. The high intake side part is not exposed to the steam space.

Embodiment FIG. 1 shows an embodiment in which this invention is applied to an internal combustion engine 1 having a slant angle of about 60°. Note that this internal combustion engine 1 has a cylinder head 2.
The exhaust valve seat (not shown) is slanted in such a direction that the intake valve seat (not shown) is on the upper side, and the intake manifold 3 is slanted on the side of the cylinder head 2 that faces diagonally upward. , an exhaust manifold 4 is attached to each side facing diagonally downward.

The water jacket 5 of the internal combustion engine 1 includes a cylinder block side water jacket 8 formed in the cylinder block 6 so as to surround the cylinder 7, and a cylinder block side water jacket 8 formed in the cylinder head 2 to cover the combustion chamber wall 9, etc. The cylinder head side water jacket 10 is formed, and both communicate through a plurality of communication holes 11, and are integrated as a whole. Here, as shown in FIG. 2, the communication hole 11 is formed only in the intake side portion which becomes higher due to the slant of the internal combustion engine 1, and is in a non-communicating state in other portions. In addition,
Specifically, the communication hole 11 is connected to the cylinder block 6.
It has a communication hole 11a along the side of the cylinder block 6 and a communication hole 11b located between the cylinders, and the latter communication hole 11b is also located considerably above the center line l of the upper surface of the cylinder block 6, that is, on the intake side.

One or more refrigerant supply ports 12 are formed in the lower part of the exhaust side of the cylinder block side water jacket 8. The tip of a refrigerant passage 15 equipped with a refrigerant supply pump 16 is connected to this refrigerant supply port 12 , and a condenser 13 is connected to the refrigerant supply port 12 .
The condensed liquid refrigerant is fed from the lower tank 14 of the refrigerant. Further, a plurality of steam outlets 17 are formed in the upper part of the water jacket 10 on the cylinder head side, specifically, in the upper part of the side surface on the intake side. This steam outlet 17 has a steam manifold 1 that collects steam from each steam outlet 17.
8 is connected thereto, and further communicates with an attenuator tank 20 of the condenser 13 via a steam passage 19.

Note that the steam manifold 18 can also be formed integrally with the intake manifold 3, as shown in FIG. FIG. 3 shows an example of such a configuration, in which steam ports 22 are opened above the intake ports 21 opened for each cylinder, and these are gathered in a steam manifold portion 18'. The steam manifold section 18'
A steam outlet 23 is formed at one end of the steam outlet 23 and is connected to the steam passage 19 described above. 24 is an intake collector section.

Further, a liquid level sensor 25 whose tip is a detection part is inserted into the upper wall of the water jacket 10 on the cylinder head side, and a temperature sensor 26 consisting of a thermistor or the like is placed on the side surface on the exhaust side.
is installed. The liquid level sensor 25 detects the presence or absence of a liquid phase refrigerant based on, for example, a change in electrical conductivity. It is set at a position somewhat lower than the upper end of the cylinder 7 on the intake side, and a sufficiently large steam space is secured above it.

Now, in the above configuration, the refrigerant supply pump 16 operates based on the detection signal of the liquid level sensor 25.
The liquid refrigerant is replenished so that the refrigerant level is always maintained near the set level through ON/OFF control. It flows through the inside to the upper part of the intake side of the water jacket 8 on the cylinder block side, and from here to the communication hole 11.
Through the cylinder head side water jacket 1
It will flow to 0. Here, the communication hole 1
1 is provided only on the high-level intake side, so that the refrigerant liquid level does not drop below the communication hole 11 in the water jacket 8 on the cylinder block side, and the liquid phase is always maintained. It remains filled with refrigerant. Therefore, even though the set level in the water jacket 10 on the cylinder head side is lower than the upper end of the cylinder 7 on the intake side, there is no risk that the upper end of the cylinder 7 will be exposed in the steam space, and a good condition is always maintained. Cooling takes place.

Note that boiling of the refrigerant occurs in both the water jacket 8 on the cylinder block side and the water jacket 10 on the cylinder head side, but the calorific value of each is usually nearly twice as large in the cylinder head 2 as in the cylinder block 6. The drop in the liquid level of the refrigerant due to boiling always occurs first in the water jacket 10 on the cylinder head side. Therefore, before the refrigerant liquid level in the cylinder block side water jacket 8 drops, the liquid level sensor 25 detects a drop in the refrigerant liquid level in the cylinder head side water jacket 10 and replenishes the liquid phase refrigerant. Since the water jacket 8 on the cylinder block side and the water jacket 10 on the cylinder head side are both reliably maintained at a predetermined liquid level position.

Effects of the invention As is clear from the above explanation, in the boiling cooling system for an internal combustion engine according to this invention, even in an internal combustion engine with a considerably large slant angle, the upper end of the cylinder is exposed to the steam space. There is no fear, and it is possible to reliably prevent poor cooling of the upper end of the cylinder, which is a region with a high heat load. Further, the liquid level itself in the water jacket on the cylinder head side does not need to be set so high, a sufficient steam space can be secured, and there is no risk of increasing the size of the cylinder head.

[Brief explanation of the drawing]

Fig. 1 is a configuration explanatory diagram showing one embodiment of the evaporative cooling device according to this invention, Fig. 2 is a top view of the cylinder block showing the arrangement of its communication holes, and Fig. 3 shows the steam manifold integrated with the intake manifold. FIG. 3 is a front view of an intake manifold showing an example of the formed structure. 1...Internal combustion engine, 8...Cylinder block side water jacket, 10...Cylinder head side water jacket, 11...Communication hole, 12...
Refrigerant supply port, 17... Steam outlet, 25... Liquid level sensor.

Claims (1)

[Scope of utility model registration request] The exhaust valve seat of the cylinder head is on the lower side,
It is applied to internal combustion engines in which the center axis of each cylinder is arranged at an angle with respect to the vertical line so that the intake valve seat is on the upper side. In an evaporative cooling system for an internal combustion engine that cools various parts, a refrigerant supply port through which liquid phase refrigerant is sent from a condenser by a refrigerant supply pump is formed at a relatively lower part of the water jacket on the cylinder block side, and A communication hole that communicates between the cylinder head and the water jacket on the cylinder head side is opened only on the high-level intake side, and a liquid level sensor that detects the height of the refrigerant liquid level is installed in the water jacket on the cylinder head side. A boiling cooling device for an internal combustion engine characterized by: