JPH02115515A - Cooler for multi cylinder engine using air and oil cooling jointly - Google Patents

Abstract

PURPOSE:To cool efficiently the whole of an engine, by connecting liquid pool chambers formed at a cylinder main body, to a lubrication oil pump and at the same time, connecting cooling liquid delivery passages formed at a head block, to the lubrication oil pump. CONSTITUTION:Cooling liquid chambers 14 are formed around sub chambers 13 provided at a head block 3. Liquid pool chambers 9 formed at a cylinder block 2 are made to communicate with a lubrication oil pump. Cooling lubrication oil pressure delivery passages 10 formed at the head block 3 are made to communicate with the lubrication pump. Cooling lubrication oil which has cooled a part between cylinders 8, circulates within the head block 3 in parallel with cooling lubrication oil supplied to each cooling liquid chamber 14, and then, is delivered into an oil cooler 18. Thus, the whole of an engine can be efficiently cooled.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a cooling system for an in-line multi-cylinder engine, and in particular, to a cooling system for an in-line multi-cylinder engine. Regarding equipment.

(Prior art) Conventional multi-cylinder diesel engines are cooled by cooling water flowing through the water jacket formed around the cylinders and in the combustion chamber layer, or by using cooling air blown by a cooling fan driven by the engine. It was used to cool the engine by spraying it onto the engine itself.

(Problem to be Solved) In a diesel engine, fuel is injected into combustion air compressed by a piston and combusted, but this combustion is performed with the piston at a position near top dead center.

Since the cylinder head portion is directly heated by this combustion, it is necessary to sufficiently cool that portion, but the lower circumferential wall of the cylinder barrel portion is heated to a lower degree than the combustion chamber portion. In consideration of friction with the piston, it is desirable to maintain the lower peripheral wall portion of the cylinder barrel at a high temperature to the extent that the piston does not seize.

By the way, in a water-cooled engine, a water jacket is formed inside the engine body, and a single system of cooling water is circulated within the water jacket, so cooling of the cylinder barrel part is moderate and the combustion chamber part is cooled. Since it is not possible to use a cooling method that uses powerful cooling, there is a problem that optimal cooling performance cannot be obtained.In addition, since the water jacket must be filled with cooling water, the engine itself This increases the weight, requires a heat radiating device (for example, a radiator) to dissipate the heat retained in the cooling water, increases the size of the engine unit, and has a problem that its applications are limited.

On the other hand, in an air-cooled engine, heat is exchanged through contact between the circulating air and the engine wall, so the degree of cooling due to the heat exchange is low.

For this reason, it is difficult to sufficiently cool the area around the combustion chamber, which tends to become hot, especially heat storage areas such as the pre-chamber and a part of the nozzle holter, and there is also the problem of loud engine noise.

Therefore, in a single-cylinder diesel engine, a coolant chamber is formed in the subchamber part formed in the head block.
It has been proposed to cool the pre-chamber part with cooling fluid and the pond part with cooling air, but in the case of a single cylinder engine, the area around the cylinder and head block comes into contact with the cooling air. Since it is easy to use, a considerable cooling effect can be expected, but even if the structure of a single-cylinder engine is applied as is to a multi-cylinder engine, there is a problem that the heat storage part that occurs between the cylinders cannot be cooled sufficiently. .

For this reason, it is conceivable to form cooling air passages between the cylinders, but if this is done, there is a problem that the cylinder pitch becomes large and the overall size of the engine increases.

The present invention has been made with attention to such points, and an object of the present invention is to provide an in-line multi-cylinder engine that has a small cylinder pitch and yet has high cooling performance.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, coolant chambers are formed around subchambers provided in the head block in a state corresponding to each cylinder of an in-line multi-cylinder air-cooled engine. A coolant supply path for feeding the coolant to the coolant chamber is formed to pass through a portion between the intake valve and the exhaust valve, and the coolant chambers are communicated with each other by a communication path,
A vertically elongated liquid reservoir is formed in the cylinder body between the cylinders that are adjacent to each other in the front and back, a recess is formed in the bottom of the head block corresponding to this liquid reservoir forming part, and this recess communicates with the coolant chambers. communicate with the communication path that is
The liquid reservoir chamber formed in the cylinder body is communicated with the lubricant pump, and the coolant supply path formed in the head block is communicated with the lubricant pump, and the return oil from the coolant chamber is passed through the oil cooler to the oil pan. It is characterized by being configured so that it can be sent back to.

(Function) In the present invention, coolant chambers are formed around subchambers provided in the head block in a state corresponding to each cylinder of an in-line multi-cylinder air-cooled engine, and coolant is supplied to the coolant chambers. The coolant supply path is formed so as to pass through the part between the intake valve and the exhaust valve, and each coolant chamber is communicated with a communication path, and a vertically long line is formed in the cylinder body between the cylinders that are adjacent to each other in the front and back. A liquid reservoir is formed, a recess is formed in the bottom surface of the head block corresponding to the liquid reservoir forming part, and this recess is communicated with a communication passage connecting the coolant chambers, which is formed in the cylinder body. The liquid reservoir chamber is connected to the lubricating oil pump, and the coolant supply path formed in the head block is connected to the lubricating oil pump, so that the return oil from the coolant chamber is sent back to the oil pan via the oil cooler. As a result, the heat storage section in the engine is efficiently cooled using a portion of the lubricating oil. In addition, the cooling lubricant that has cooled the area between the cylinders flows in parallel with the cooling lubricant that is supplied to each coolant chamber in the head block, and then is sent to the oil cooler, which cools the area between the cylinders. The high-temperature cooling fluid after cooling does not affect the cooling of the subchamber.

(Embodiment) The drawings show an embodiment of the present invention, in which Fig. 1 is a bottom view of the cylinder head of a two-cylinder diesel engine, Fig. 2 is a longitudinal cross-sectional side view of the two-cylinder diesel engine, and Fig. 3 is a longitudinal cross-section of the main parts. The rear view and FIG. 4 are plan views of the cylinder block portion.

This engine has a crankcase (1) and a cylinder block (2) integrally formed.
A head block (3) is fixed on the upper side to form an engine body (E), and a cooling fan (
6) is fixed, the cooling fan (6) is surrounded by a wind guide case (7), and the cooling air generated by the cooling fan (6) is sent to the cylinder block (2) section and the head block (3) section. This is to cool the engine.

The cylinder block (2) has vertically oriented cylinders (8).
are arranged in series, and a vertically elongated liquid reservoir chamber (9) is formed on the wall of the cylinder block (2) located between the two cylinders.
is formed. The upper end surface of this liquid reservoir chamber (9) opens to the upper surface of the cylinder block, that is, the head block mounting surface, and its cross section is an oval shape with a constricted center as shown in FIG. It is formed. In addition, a cooling lubricant oil pressure passage (lG) is vertically formed in the wall of the cylinder block (2) on the side where the bushing rod is disposed.

The head block (3) has intake valves (
A spherical auxiliary chamber (13) is located on one side of the line connecting the cylinder center between the intake valve (11) and the exhaust valve (12) in each cylinder. ) is formed. A coolant chamber (14) is formed outside the sub-chamber (13) to surround the sub-chamber (13),
The head block (3) is configured so that the coolant is supplied to the coolant chamber (14) through a coolant passage (15) provided through the bottom wall portion of the head block (3). In addition, this coolant passage (15)
is formed to pass between the valves of the intake valve (11) and the exhaust valve (12) in each cylinder, so that when the coolant flows into the coolant chamber (14), the space between the valves is cooled. It is. Further, the two coolant chambers (14) are communicated with each other by a communication passage (16), and the coolant flowing into the coolant chamber (14a) located on the far side from the cooling fan (6) is transferred to the coolant chamber (14). The oil flows into the coolant chamber (14b) located near the oil cooler (18) through the discharge passage (17).

Further, a recess (19) having a substantially triangular cross section is provided at a location corresponding to the liquid reservoir chamber (9) on the bottom surface of the head block (3), that is, the surface located on the cylinder block side. The recess (19) is connected to the communicating path (16) by a connecting path (20). Also, Head Pro, Ri (3)
A planar arc-shaped recess (21) is provided at the peripheral edge of each cylinder-corresponding part on the bottom surface of the cooling lubricant oil pressure passage (10).
It is formed to correspond to.

The liquid, retaining chamber (9) and cooling lubricating oil pressure passage (1
0) is a lubricating oil pump (
23), and is supplied with pressurized lubricating oil or relieved lubricating oil. Oil cooler (
The cooling lubricating oil cooled in step 18) is returned to the oil pan (26) in the crankcase (1) through a return oil passage (25) defined in the bushing rod insertion hole (24). There is. The oil cooler (18) is placed in the upper part of the air guide case (7) with its lower part protruding, and exchanges heat with the cooling air blown by the cooling fan (6). In particular, it is intended to cool the cooling lubricant flowing inside.

In addition, there is a cooling air passage (27) inside the head block (3).
is formed, and the head block (3) is air-cooled by the cooling air blown by the cooling fan (6) flowing through the cooling air passage (27) in the head block (3).

The reference numeral (28) in the figure is a relief valve disposed in the cooling fluid passage (15), and its discharge port is the return passage (25) for the cooling lubricating oil.
is connected to.

In the cooling device configured as described above, the cooling lubricant that has reached the head block (3) from the cooling lubricant oil pressure passage (10) cools the valve gap, and then flows into the coolant chamber (14).
), the cooling lubricant supplied to the liquid reservoir chamber (9) cools the area between the cylinders, flows into the head block (3), and joins the discharge path from the coolant chamber (14). Become. For this reason, each auxiliary chamber (13) and the area between the cylinders, which are highly heated, are cooled independently by cooling lubricant oil supplied in parallel, so they are not affected by other high-temperature parts. It can be cooled efficiently.

(Effects) In the present invention, coolant chambers are formed around subchambers provided in the head block in a state corresponding to each cylinder of an in-line multi-cylinder air-cooled engine, and coolant is supplied to the coolant chambers. The coolant supply path is formed so as to pass through the part between the intake valve and the exhaust valve, and each coolant chamber is communicated with a communication path, and a vertically long line is formed in the cylinder body between the cylinders that are adjacent to each other in the front and back. A liquid reservoir is formed, a recess is formed in the bottom surface of the head block corresponding to the liquid reservoir forming part, and this recess is communicated with a communication passage connecting the coolant chambers, which is formed in the cylinder body. The liquid reservoir chamber is connected to the lubricating oil pump, and the coolant supply path formed in the head block is connected to the lubricating oil pump, so that the return oil from the coolant chamber is sent back to the oil pan via the oil cooler. Therefore, a part of the lubricating oil is used to cool the heat storage part in the engine. In this case, lubricating oil has a higher cooling efficiency than air, so it can efficiently cool the entire engine, and even if the contact area with the cooling medium is smaller than that of air-cooled oil, sufficient cooling performance can be achieved. Since the cooling medium passage can be formed narrowly, the engine can be made smaller.

In addition, the cooling lubricant that has cooled the area between the cylinders flows in parallel with the cooling lubricant that is supplied to each coolant chamber in the head block, and then is sent to the oil cooler, which cools the area between the cylinders. The high-temperature cooling fluid after cooling does not affect the cooling of the subchamber.

As a result, the present invention can provide an in-line multi-cylinder engine with high cooling performance while having a small cylinder pitch.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a bottom view of a cylinder head of a two-cylinder diesel engine, FIG. 2 is a longitudinal side view of the two-cylinder diesel engine, FIG. 3 is a longitudinal rear view of main parts, and FIG. FIG. 4 is a plan view of the cylinder block portion. 3...Head block, 6...Cooling fan, 7...
・Air guide case, 8... cylinder, 9... liquid reservoir chamber,
11... Intake valve, 12... Exhaust valve, 13... Sub-chamber, 14... Coolant chamber, 15... Coolant passage,
16...Communication path, 18...Oil cooler, 19...
Recessed portion, 23... Lubricating oil pump, 26... Oil pan, E... Engine body. Patent applicant: Kubota Iron Works Co., Ltd. Representative: Hisashi Kitaya ≦゛S゛−°（Doゝ′ Figure 1

Claims (1)

[Claims] 1. The cylinders (8) are arranged in series in the front and rear, and the cooling fan (6) arranged on the front side of the engine body (E) is covered with a wind guide case (7). In an air-cooled multi-cylinder engine configured to air-cool the engine body (E) using the generated cooling air, a head block (3
) A cooling liquid chamber (14) is formed around each subchamber (13) provided in the cooling liquid chamber (14).
The coolant passage (15) that supplies coolant to the intake valve (11)
) and the exhaust valve (12), and each coolant chamber (14) is connected to a communication path (16).
), a vertically elongated liquid reservoir chamber (9) is formed in the cylinder body between the cylinders (8) which are adjacent in the front and back, and a head block (3) corresponding to the liquid reservoir chamber (9) forming part is formed.
A recess (19) is formed in the bottom surface of the cooling liquid chamber (14), and a communication path (
16), and communicates the liquid reservoir chamber (9) formed in the cylinder body with the lubricating oil pump (23),
The coolant passage (15) formed in the head block (3) is communicated with the lubricating oil pump (23), and the coolant chamber (
14) A cooling device for an oil-cooled and air-cooled multi-cylinder engine, characterized in that the oil returned from the oil cooler (18) is sent back to the oil pan (26).