JP4193246B2 - Engine cooling system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine cooling device, and more particularly to an improvement of a cylinder head side cooling device suitable for a diesel engine.
[0002]
[Prior art]
As an engine cooling device, for example, there is one proposed by JP-A-8-14101.
[0003]
In order to efficiently cool the cylinder head side, a boss portion is provided on the inner wall of the cylinder head water jacket, and a drill hole communicating with the cooling water passage on the cylinder block side is formed in the boss portion. By decentering from the center of the boss, the direction of the opening in the boss is determined, and this direction is directed to the portion with the highest heat load. It is made to erupt toward the high part.
[0004]
By doing in this way, it is trying to cool efficiently by inducing a cooling water with a low block side temperature rather than a cooling water with a high temperature in a cylinder head in a part with high heat load.
[0005]
[Problems to be solved by the invention]
However, even if a boss projecting on the inner wall of the water jacket on the cylinder head side is provided in this way and a drill hole for directing cooling water from the block side is made here, such a boss must be It is not always provided near the high part of the valve, and a boss part is provided in the narrow part between each valve seat of the intake valve and the exhaust valve, or the part between these and the support hole of the fuel injection valve. Inducing cooling water from the block side was almost impossible, especially for small multi-cylinder engines with little space.
[0006]
In particular, when the fuel injection valve is installed in the center of the combustion chamber, the intake valve and the exhaust valve are arranged on both sides of the fuel injection valve. Therefore, cooling around the fuel injection valve is very difficult, and the cooling of the intake and exhaust valves is insufficient. Therefore, there is a risk of causing problems such as deterioration of properties of the injected fuel, suction, abnormal wear of the exhaust valve, poor sealing, and the like.
[0007]
The present invention has been proposed in order to solve such a problem, and directs the low-temperature cooling water from the cylinder block side directly to the suction and exhaust valves and the fuel injection valve around the cylinder head side. The aim is to obtain high cooling performance as possible.
[0008]
[Means for Solving the Problems]
A first invention is an engine in which a fuel injection valve is attached to a cylinder head, an intake valve and an exhaust valve are arranged, and a water jacket for guiding cooling water around the fuel injection valve and the intake / exhaust valve is formed inside the cylinder head. In this cooling device, a cooling water conduction path is formed in the wall of the cylinder head between the valve seats of the intake valve and the exhaust valve and toward the fuel injection valve, and this cooling water conduction path is formed by multistage drilling. and forming a drill hole from sequentially different diameter and so as to the cylinder head side in the middle, and the base end communicates with the cooling water passage of the cylinder block, the previous end in the vicinity of the fuel injection valve Ru is communicated with the cylinder head side of the water jacket.
[0009]
According to a second aspect of the present invention, there is provided a cylinder head provided with a drill hole from the lower surface of the cylinder head communicating with the cylinder block side cooling water passage on the proximal end side of the cooling water passage and communicating with a water jacket on the cylinder head side on the distal end side. Drill holes from the top were provided.
[0010]
In a third aspect based on the second aspect, the drill hole from the upper surface of the cylinder head is formed through a core core hole in the head jacket.
[0012]
According to a fourth invention, in the first to third inventions, the diameter of the drill hole at a portion where the cooling water conducting path communicates with the water jacket is made larger than the diameter of the drill hole at a portion located between the valve seats.
[0013]
In a fifth aspect based on the first to third aspects, the portion where the cooling water conducting path communicates with the water jacket is formed by a plurality of drill holes.
[0014]
According to a sixth aspect of the present invention, in the first to third aspects of the present invention, a drill hole is formed so that the portion where the cooling water conducting path communicates with the water jacket is substantially parallel to the fuel injection valve.
[0015]
[Operation and effect of the invention]
In the first invention, not only cooling by a water jacket on the cylinder head side but also a cooling water conducting path that passes between the valve seats of the intake valve and the exhaust valve and goes to the fuel injection valve is provided in the cylinder head. Low-temperature cooling water from the side is directly guided, thereby cooling the space between the valve seats and the vicinity of the fuel injection valve, thereby improving the cooling performance. For this reason, abnormal wear due to thermal deformation of the valve seats of the intake and exhaust valves can be prevented, good sealing performance can be maintained, and malfunctioning and deterioration of sealing performance associated with high temperature of the fuel injection valve can be prevented.
In addition, workability is good because the cooling water passage is formed by drilling with a drill. In addition, the multi-hole drilling has a shape with different hole diameters on the way, so the processing depth and processing speed for each drill can be selected, and the processing accuracy is improved compared to single-diameter drill hole processing. Holes can be drilled to the limit, improving cooling performance by increasing the hole diameter, and improving productivity by speeding up processing.
[0016]
In the second and third inventions, since the cooling water passage is formed by drilling with a drill, workability is good. Especially for drilling from the upper surface of the cylinder head, if a core core hole is used, the subsequent blinding is performed. It is not necessary to seal with a stopper, and productivity is improved.
[0018]
In the fourth to sixth inventions, the cooling water in the vicinity of the fuel injection valve can be increased to enhance the cooling effect of the fuel injection valve.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0020]
1 to 3, the present invention is applied to a four-cylinder diesel engine equipped with a common rail type fuel injection device. The cylinder head 1 has a fuel injection valve positioned substantially at the center of each cylinder. 2 is attached. The fuel injection valve 2 is inserted into a support hole 3 provided in the cylinder head 1 via a sheet material 4, and is fixed by a fixing bolt 6 while being supported by a fixture 5. The tip of the fuel injection valve 2 penetrates from the injection valve hole 7 of the cylinder head 1 to the lower surface of the cylinder head, and injects fuel into a combustion chamber (not shown).
[0021]
The combustion chamber is formed between the lower surface of the cylinder head 1, a cylinder bore of a cylinder block (not shown), and a piston that slides therein.
[0022]
High pressure fuel is fed into the fuel injection valve 2 from a common rail 9 supported on the top of a box-shaped cam carrier 8 attached to the upper surface of the cylinder head 1, and the fuel injection valve (solenoid valve) opens and closes according to operating conditions. By doing so, the high-pressure fuel accumulated in the common rail 9 is injected. The cam carrier 8 supports the camshaft 10 so as to freely rotate. The cam carrier 8 suppresses generation of vibration associated with the rotation of the camshaft 10 by a highly rigid box structure.
[0023]
A water jacket 11 is formed inside the cylinder head 1, and a plurality of passages in which cooling water that has cooled the cylinder block extends vertically through the lower deck 13 around the cylinder bore, as shown in FIG. 12 is introduced. In addition, the shape and cross-sectional area of each channel | path 12 differ according to a request | requirement.
[0024]
As shown in FIGS. 1 and 3, the water jacket 11 is provided around the fuel injection valve 2, the intake port 14, the intake valve valve seat 15, the intake valve shaft guide hole 16, the exhaust port 17, and the exhaust valve. A cooling space into which the cooling water is guided, including the periphery of the valve seat 18 and the exhaust valve shaft guide hole 19, is formed inside the cylinder head.
[0025]
However, as shown in FIG. 3, the narrow portions sandwiched between the valve seats of the intake and exhaust valves and the support hole 7 of the fuel injection valve 2 are connected to each other by the wall thickness of the cylinder head 1. The space part of the water jacket 11 is not formed.
[0026]
However, as shown in FIG. 1, a coolant passage 21 is formed between the valve seats 15 and 18 so as to be substantially parallel (substantially horizontal) to the lower surface of the cylinder head. The cooling water conducting path 21 is formed toward the fuel injection valve 2 through the valve seats.
[0027]
In this case, the cooling water conduction path 21 is formed by drilling horizontally from the side surface of the cylinder head substantially orthogonal to the center line of the cylinder head row, and the open end on the base end side is sealed by the blind plug 22. From the lower surface of the cylinder head, a vertical water guide hole 23 that penetrates through the lower deck 13 by drilling and communicates with the base end side of the coolant water passage 21 is formed. Connecting to the water passage, the cooling water having a low temperature is directly led from the cylinder block side. Further, a drainage hole 25 formed in the vicinity of the support hole 7 of the fuel injection valve 2 through the upper deck 24 by drilling from the upper surface of the cylinder head 1 is provided at the front end side of the cooling water passage 21. The cooling water flows out of the water jacket 11 from 25. A portion that penetrates the door upper deck 24 during drilling is sealed with a blind plug 26 to prevent water leakage from the water jacket 11.
[0028]
In FIG. 2 when the cylinder head 1 is viewed from the lower surface side, a head bolt hole 27 is formed around each cylinder, and a plug hole of a glow plug 28 is formed in the vicinity of the injection valve hole 7 of the fuel injection valve 2. 29 is provided.
[0029]
It is comprised as mentioned above, Next, an effect | action is demonstrated.
[0030]
Cooling water guided from the cylinder block (not shown) circulates in the water jacket 11 of the cylinder head 11 to cool each part of the cylinder head. However, the vicinity of the fuel injection valve 2 and the intake and exhaust valve seats 15 and 18 are in a space-tight state, so that the cylinder head wall is connected to each other and it is difficult to form a sufficient cooling space. In addition to being difficult to receive a direct cooling action by the cooling water of the jacket 11, the cooling water filling the water jacket 11 is also high in temperature, so that the cooling tends to be insufficient.
[0031]
However, a cooling water conducting path 21 is formed in the wall of the cylinder head between the valve seats 15 and 18, and low-temperature cooling water is guided directly from the cylinder block side through the water guiding holes 23. . This cooling water conduction path 21 extends to the vicinity of the fuel injection valve 2 and rises upward from here. For this reason, the space between the valve seats of the intake / exhaust valves that are difficult to be cooled is directly cooled by the relatively low-temperature cooling water, and the temperature rise is effectively suppressed. As a result, abnormal wear due to insufficient strength due to high temperatures of the valve seats 15 and 18 and poor sealability due to thermal deformation are improved.
[0032]
Further, the cooling water cools the surroundings of the fuel injection valve 2 to improve the efficiency of fuel coking and electromagnetic coil cooling, and can prevent the fuel injection valve 2 from becoming hot. In particular, in common rail type fuel injection, the fuel injection timing and the number of injections can be controlled freely, so the number of operations of the fuel injection valve 2 increases, and the temperature easily rises. In this way, efficient cooling can be performed. As a result, temperature rise can be avoided reliably.
[0033]
The cooling water introduced from the cylinder block side introduced into the cooling water passage 21 merges with the water jacket 11 of the cylinder head 1 through the discharge hole 25. The cooling water flow is upstream on the cylinder block side. Because the pressure is high, it is possible to smoothly flow the cooling water from the water guide hole 23 to the drain hole 25 without using a special mechanism for pumping the cooling water, and reliable cooling performance is maintained under all operating conditions. Is done.
[0034]
Next, another embodiment will be described.
[0035]
4 to FIG. 6 is one in which three stages of drill holes with different hole diameters are provided as shown in the figure when the cooling water passage 21 is formed by drilling.
[0036]
Formed from a large-diameter one-stage hole 31, a medium-diameter two-stage hole 32, and a small-diameter three-stage hole 33, the first-stage hole 31 is first drilled, and then a narrower two-stage hole 32, three-stage hole. Multi-stage machining such as machining the hole 33 increases machining speed and machining accuracy compared to drilling a single-diameter drill, and expands the drill diameter to the limit of the valve seat, cooling Performance can be improved.
[0037]
Further, since the discharge hole 25 for drilling from the upper deck 24 side is processed through the head jacket core hole 35 for core sand removal provided in the upper deck 24, there is a plug body 36 of the core hole 35. It is not necessary to seal the drill hole with a blind plug later.
[0038]
7 is a drain hole 25a having a hole diameter larger than that of the cooling water passage 21, and this makes it easier to guide more cooling water near the seat surface of the fuel injection valve 2. The cooling performance is improved.
[0039]
The thing of FIG. 8 is also made into the duplication circular hole cross section which spreads in the direction between each valve seat by giving two drill hole processing as the drainage hole 25b, and overlapping the cross section of both drill holes in part, and cooling. The cooling performance near the seat surface of the fuel injection valve 2 is improved by increasing the amount of water.
[0040]
The thing of FIG. 9 is provided with the drainage hole 25c provided substantially perpendicularly so that it may become substantially parallel to the fuel injection valve 2, and it can guide a cooling water over a long area along the fuel injection valve 2 so much, A high effect is produced in improving the cooling performance of the fuel injection valve 2.
[0041]
Each of the above-described embodiments shows an example in which the present invention is applied to a diesel engine. However, the present invention is not limited to this, and a so-called direct injection gasoline engine that directly injects fuel into a cylinder via a fuel injection valve. The same cooling mechanism can be applied not only around the fuel injection valve but also around the spark plug.
[0042]
The present invention is not limited to the above-described embodiments, and it is obvious that various modifications can be made within the scope of the technical idea of the present invention.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.
FIG. 2 is an A arrow view of FIG.
3 is a cross-sectional view taken along the line BB in FIG.
FIG. 4 is a cross-sectional view of a main part of a second embodiment.
FIG. 5 is also a C arrow view thereof.
FIG. 6 is a cross-sectional view taken along DD and EE, respectively.
FIG. 7 is a cross-sectional view of a third embodiment.
FIG. 8 is a cross-sectional view of a fourth embodiment.
FIG. 9 is a cross-sectional view of main parts of a fifth embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Fuel injection valve 11 Water jacket 15 Valve seat 18 Valve seat 21 Cooling water passage 23 Water guide hole 25 Drain hole

Claims (6)

In an engine cooling device in which a fuel injection valve is attached to a cylinder head, an intake valve and an exhaust valve are arranged, and a water jacket that guides cooling water around the fuel injection valve and the intake / exhaust valve is formed inside the cylinder head.
Forming a cooling water conduction path that passes between the valve seats of the intake valve and the exhaust valve in the wall of the cylinder head and faces the fuel injection valve;
The cooling water conduits, thereby forming a drill hole in the cylinder head side so as to sequentially different hole diameter in the middle by a multistage drilling, communicates the base end side in the cooling water passage of the cylinder block the cooling system for an engine according to claim Rukoto is communicated with the cylinder head side water jacket to-edge side in the vicinity of the fuel injection valve. A drill hole from the lower surface of the cylinder head that communicates with the cylinder block-side coolant passage is provided on the proximal end side of the cooling water passage, and a drill hole from the upper surface of the cylinder head that communicates with the water jacket on the cylinder head side is provided at the distal end side. The engine cooling device according to claim 1 provided.   The engine cooling device according to claim 2, wherein the drill hole from the upper surface of the cylinder head is formed through a core jacket core hole. The engine cooling device according to any one of claims 1 to 3, wherein a diameter of a drill hole at a portion where the cooling water conducting path communicates with a water jacket is larger than a diameter of a drill hole at a portion located between valve seats. The engine cooling device according to any one of claims 1 to 3 , wherein a portion where the cooling water conduction path communicates with the water jacket is formed by a plurality of drill holes. The engine cooling device according to any one of claims 1 to 3 , wherein a portion where the cooling water conduction path communicates with the water jacket is drilled so as to be substantially parallel to the fuel injection valve.

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