JPH06577Y2 - Engine cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a cooling device for a cylinder head in an overhead valve (OHV) type engine.

(Prior Art) Conventionally, in an overhead valve type engine in which an intake / exhaust valve arranged in a cylinder head is opened / closed according to rotation of a cam shaft in a cylinder block, a cam shaft and a rocker arm are connected to each other. A push rod that passes through the cylinder head in the vertical direction (see, for example, Japanese Utility Model Laid-Open No. 61-76101).

Further, in an engine in which an exhaust port for discharging exhaust gas from the combustion chamber is opened to one side of the cylinder head and a fuel injection valve is installed facing this combustion chamber, the fuel injection valve is affected by heat from the exhaust port. To avoid this, it is considered that the exhaust push rod for opening and closing the exhaust valve is installed on the side opposite to the exhaust port so as to penetrate through the push rod hole installed on the exhaust port side.

(Problems to be solved by the invention) However, in the above-mentioned exhaust push rod in the engine of the overhead valve type in which the exhaust push rod hole for inserting the exhaust valve driving push rod is formed on the exhaust port side as described above. The hole portion receives the heat of the exhaust port and becomes a high temperature state, the temperature of the exhaust valve driving push rod that penetrates inside rises, the push rod expands due to thermal expansion, and the exhaust valve opens via the rocker arm. Since the valve is biased in the valve direction, the opening / closing timing of the exhaust valve may deviate from the set timing.

Further, when the gap around the push rod outer periphery of the exhaust push rod hole is used as a blow-by gas passage,
When the temperature of the push rod hole rises, the oil mixed in the blow-by gas flowing inside may be carbonized and adhered and deposited, which may hinder the flow of the blow-by gas.

In view of the above circumstances, the present invention has an object to provide an engine cooling device in which the exhaust push rod hole portion is effectively cooled by effectively utilizing a narrow space.

(Means for Solving the Problems) In order to achieve the above object, the cooling device of the present invention is provided with an exhaust push rod hole through which the exhaust valve driving push rod is inserted, on the side where the exhaust port is provided with respect to the cylinder row. With
An inter-valve cooling water hole for supplying cooling water to the intervalve portion where the intake port and the exhaust port are close to each other is formed so as to intersect with the exhaust push rod hole, and the inter-valve cooling is provided in the exhaust push rod hole on the outer periphery. A guide sleeve for forming a cooling water introduction gap communicating with the water hole is attached.

(Function) In the engine cooling device as described above, a guide sleeve that forms a cooling water introduction gap is attached to the outer periphery of the exhaust push rod hole formed near the exhaust port, and cooling water is supplied to the intervalve portion. The inter-valve cooling water hole is bored so as to intersect with the exhaust push rod hole, and the cooling water is introduced from the inter-valve cooling water hole into the cooling water introduction gap of the guide sleeve to cool this portion, and then the exhaust port The influence of heat is reduced, and the push rod for driving the exhaust valve is prevented from expanding.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. 1 is a sectional plan view of an OHV type cylinder head of a 4-cylinder diesel engine, FIG. 2 is a longitudinal sectional view of a main part of the cylinder head, and FIG. 3 is a sectional view taken along line III-III of FIG. ,
The left half of FIG. 1 shows a cross section taken along line I-I of FIG. 2, and the right half shows a cross section taken along I′-I ′.

In the bottom wall 2a of the cylinder head 2 of the engine 1, the combustion chamber side openings 3a and 4a of the intake port 3 and the exhaust port 4 communicating with the combustion chamber C (see FIG. 2) of each cylinder are opened. There is. On the downstream side of the exhaust port 4 of each cylinder, a connection port 4b is opened at one side A (exhaust side) with respect to the cylinder row of the cylinder head 2, and is connected to an exhaust passage (not shown). On the other hand, on the upstream side of the intake port 3 of each cylinder, a connection port 3b opens on the other side B (intake side) with respect to the cylinder row, and is connected to an intake passage (not shown).

Further, the injection valve mounting hole 5 for mounting a combustion injection valve (not shown) for injecting fuel into the combustion chamber C is provided in the combustion chamber C.
It is formed at a position displaced from the center of the intake side to the intake side. The exhaust port 4 is formed substantially linearly, while the intake port 3 is formed in a spiral shape in the vicinity of the combustion chamber side opening 3a.

Both combustion chamber side openings 3 of the intake port 3 and the exhaust port 4
Valve seats 6 and 7 are attached to a and 4a, respectively, and exhaust valves are seated in intake valves (not shown). The valve shafts of the intake valve and the exhaust valve penetrate the respective valve shaft insertion holes 8 and 9 upward and are linked to a valve mechanism (not shown). This valve operating mechanism includes intake and exhaust push rods 10 and 11 connected to a rocker arm linked to intake and exhaust valves.
(See FIG. 3) is configured as an OHV type so as to penetrate the cylinder head 2 in the vertical direction and follow the cam shape of the cam shaft in the cylinder block.

The intake and exhaust push rod holes 12 and 13 through which the intake and exhaust push rods 10 and 11 are inserted are arranged side by side on the opening side A of the exhaust port 4 with respect to the cylinder row. Further, six head bolt holes 14 for inserting head bolts for fastening the cylinder head 2 to the cylinder block are located at equal intervals on the outer peripheral side of the circle corresponding to the combustion chamber C of each cylinder, between cylinders, front and rear ends. Formed on both sides of the center of the cylinder.

In the space between the upper wall 2b and the bottom wall 2a of the cylinder head 2, a portion except the intake port 3 and the exhaust port 4 is formed as a main cooling water passage 15. This main cooling water passage 1
5, the cooling water rising from the cylinder block is introduced by the inlet port 15a opened in the bottom wall 2a on the exhaust side, and the communication hole 17 opened in the valve portion in the central portion where the intake port 3 and the exhaust port 4 are close to each other. And communicates with the inter-valve cooling water hole 18 formed near the lower valve seats 6 and 7.

The inter-valve cooling water hole 18 is bored from the side surface of the cylinder head 2 on the exhaust side A, and the inter-valve cooling water hole 18 intersects with the exhaust push rod hole 13 so that they communicate with each other. And a closing plug 22 is attached to the open end thereof.

The cooling water flows into the inter-valve cooling water hole 18 from the introduction passage 19 which is open in the middle of the hole. The introduction passage 19 is formed obliquely and has one end opening to the bottom surface of the cylinder head 2, and communicates with the cooling water passage of the cylinder block to supply cooling water. Cooling water is supplied to the vicinity of the valve seats 6 and 7 in the intervalve portion where the intake port 3 and the exhaust port 4 are close to each other, and the intercooling portion is cooled by passing upward through the communication hole 17 and then the main cooling water passage 15 Flow into.

A pipe-shaped guide sleeve 20 is fitted in the exhaust push rod hole 13. The guide sleeve 20 has a small-diameter recess on the outer periphery of the intermediate portion except the upper and lower ends, and is provided so as to form a cooling water introduction gap 21 between the guide sleeve 20 and the inner surface of the push rod hole 13 on the outer periphery. . The inter-valve cooling water hole 18 communicates with the lower part of the cooling water introduction gap 21, and the upper end communicates with the main cooling water passage 15 near the exhaust port 4, and the cooling water flows from the inter-valve cooling water hole 18 into the main cooling water passage 15. The cooling water that has flowed into the introduction gap 21 rises through the introduction gap 21 and flows into the main cooling water passage 15.

The guide sleeve 20 is formed by applying a sealant to the outer peripheral surfaces of the upper and lower ends and then press-fitting it into the exhaust push rod hole 13 to ensure the sealing property between the two.

On the other hand, the space between the exhaust push rod hole 13 and the exhaust push rod 11 is formed as a blow-by gas ascending passage, communicates with the crankcase of the cylinder block, and its upper end is formed to a high position. The oil is prevented from flowing into the upper part of the cylinder head. Further, the outer circumference of the intake push rod 10 of the intake push rod hole 12 is configured as an oil return passage, and the oil supplied to the upper portion of the cylinder head 2 is collected in an oil pan.

With the structure of the above-described embodiment, the guide sleeve 20 forming the cooling water introduction gap 21 is attached to the exhaust push rod hole 13 through which the exhaust push rod 11 is inserted, and the inter-valve cooling water hole 18 is attached to the cooling water introduction gap 21. Since the cooling water is made to flow through by connecting the
Since the water flow from the flow is high, the flow velocity is high, and since both the exhaust push rod hole 13 and the guide sleeve 20 are formed by machining, it is possible to accurately form a narrow gap that cannot be formed by casting, and high thermal conductivity, high temperature Sufficient cooling performance can be obtained even for the exhaust port wall. Further, the formation of the cooling passage in the portion of the push rod hole 13 can be water-cooled in a limited space by press-fitting the guide sleeve 20.

Further, in this embodiment, since the introduction passage 19 is opened to the intervalve cooling water hole 18 between the exhaust push rod hole 13 and the communication hole 17, both cooling actions are not hindered from each other.

(Effect of the Invention) According to the present invention as described above, a guide sleeve that forms a cooling water introduction gap is attached to the exhaust push rod hole, and the inter-valve cooling water hole is formed so as to intersect with the exhaust push rod hole. By doing so, cooling water is introduced from the inter-valve cooling water hole into the cooling water introduction gap of the guide sleeve to efficiently cool this portion, and the portion of the exhaust push rod hole receives the heat of the exhaust port and becomes high temperature. It is possible to prevent the occurrence of the state, prevent a deviation from occurring in the opening / closing timing of the exhaust valve due to the thermal expansion of the temperature of the exhaust valve driving push rod, and ensure a good opening / closing operation. Further, even when the exhaust push rod hole is used as the blow-by gas passage, it is possible to prevent the carbonization of the oil in the blow-by gas due to the temperature rise of the push rod hole.

[Brief description of drawings]

FIG. 1 is a sectional plan view showing a cylinder head structure of an overhead valve type engine equipped with a cooling device according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of a main part of the cylinder head, and FIG. FIG. 3 is an enlarged cross-sectional view taken along the line III-III in the figure. 1 ... Engine, 2 ... Cylinder head, 4 ... Exhaust port, 6,7 ... Valve seat, 11 ... Exhaust valve driving push rod, 13 ... Exhaust push rod hole, 15
...... Main cooling water passage, 17 ...... Communication hole, 18 ...... Valve cooling water hole, 19 ...... Introduction passage, 20 ...... Guide sleeve, 2
1 ... Cooling water introduction gap.

Claims (1)

[Scope of utility model registration request] 1. An overhead valve engine in which an exhaust push rod hole, through which an exhaust valve driving push rod is inserted, is provided on a side where an exhaust port is provided with respect to a cylinder row, and an intake port and an exhaust port are close to each other. An inter-valve cooling water hole for supplying cooling water to the inter-valve portion is formed so as to intersect with the exhaust push rod hole, and a cooling water introduction communicating with the inter-valve cooling water hole on the outer periphery is provided in the exhaust push rod hole. An engine cooling device comprising a guide sleeve for forming a gap.