JPH0968044A - Inter-cylinder fuel injection type 4 cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure strength near the cylinder head jointing face of a cylinder block so as to enable a compression ratio to be increased by setting a fuel injection valve on the cylinder block side so that a piston and the injection port of the fuel injection valve may overlap each other when the piston is positioned in the upper dead point. SOLUTION: In an inter-cylinder fuel injection type 4 cycle engine, plural intake air ports 12 and exhaust ports 13 are formed in a cylinder head 2 so that each one end is opened to a combustion chamber ceiling wall part 6, and an ignition plug 14 is so set as to position a discharge part approximately in the center of the ceiling wall part 6. In addition, valve recesses 9c are formed in depressed shapes in such positions as facing to respective intake/exhaust valves 15, 16 and a partial recessed part 9d is formed in a position facing to the injection port 21 of a fuel injection valve 20. And also the fuel injection valve 20 is mounted on a cylinder block 3 in such a way that the injection port 21 is positioned between a piston upper end part 9a and a top ring and the direction of fuel injection is pointed toward the combustion chamber ceiling wall part 6 when the piston 9 is positioned in the upper dead point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-cylinder fuel injection type four-cycle engine of the type in which fuel is directly injected into a combustion chamber by a fuel injection valve and then ignited by a spark plug to burn.

[0002]

2. Description of the Related Art A method of directly injecting fuel into intake air in a combustion chamber has been known for a long time in diesel engines, but even in a 4-cycle engine using gasoline as a fuel, the drawback of a carburetor has been compensated for before. It has been used in the field of high-performance engines as an engine, and recently, attention has been paid to it in terms of air pollution problems and fuel consumption. Furthermore, advances in electronic technology have made it possible to easily perform ideal control in this system. For this reason, the adoption of this method has also been considered for general passenger cars.

In such an in-cylinder fuel injection type four-cycle engine, when the load is low, the dispersion of the fuel is suppressed, and the stratified fuel is intensively supplied to the vicinity of the spark plug as the piston rises. It has been conventionally practiced to inject fuel in the latter stage of the compression stroke and to disperse the fuel during high load to inject the fuel during the intake stroke in order to improve the air utilization rate.

[0004]

In the conventional in-cylinder fuel injection type four-cycle engine as described above, the fuel injection valve is usually used so that the injection timing can be freely set without being restricted by the position of the piston. Is arranged on the cylinder head side, and the injection port of the fuel injection valve is opened to the top wall of the combustion chamber.However, the cylinder head is provided with an intake port and an exhaust port, and a spark plug is installed. Since the valves for opening and closing the intake / exhaust ports are also installed, it is difficult to lay out the fuel injection valve on the cylinder head side especially in a multi-valve engine.

Therefore, if an attempt is made to obtain a space for disposing the fuel injection valve in the cylinder head by making the top wall of the combustion chamber largely recessed, the volume of the combustion chamber at the top dead center of the piston increases, and that amount increases. This leads to a reduction in compression ratio, which hinders improvement in engine performance.

In order to solve such a problem, the fuel injection valve is installed on the cylinder block side, and in order to secure the degree of freedom of the injection timing as much as possible, the fuel injection valve is as close to the joint surface with the cylinder head as possible. It has been studied by the present applicant that the fuel injection valve is opened to inject the fuel toward the top wall of the combustion chamber. In that case, the fuel injection valve's injection port is joined to the cylinder head. If it is placed too close to the surface, problems will occur in the strength of the cylinder block near the cylinder head joint surface.

[0007]

In order to solve the above problems, the present invention provides a combustion chamber top wall formed on the lower surface of a cylinder head, as set forth in claim 1 above. The intake port and the exhaust port, which are opened and closed by valves, are opened, the discharge part of the spark plug is arranged, and the piston is slidably fitted in the cylinder hole formed in the cylinder block. A cylinder head and a cylinder block are connected so that a combustion chamber is defined by the ceiling wall portion, the cylinder hole, and the upper surface of the piston, and a fuel injection valve for directly injecting fuel into the combustion chamber is installed. In the in-cylinder fuel injection type four-cycle engine, the piston and the injection port of the fuel injection valve overlap each other when positioned at the top dead center,
The fuel injection valve is installed on the cylinder block side.

Further, in the in-cylinder fuel injection type four-cycle engine described in claim 1, when the injection port of the fuel injection valve is located at the top dead center as described in claim 2, It is characterized in that it is located between the top end of the piston and the top ring.

Further, in the in-cylinder fuel injection type four-cycle engine according to the above-mentioned claim 2, the above-mentioned claim 3 is used.
As described in (1), a concave portion that overlaps the injection port at the position of the top dead center is partially formed at a position facing the injection port on the upper surface of the piston.

Further, in the in-cylinder fuel injection type four-cycle engine described in claim 1, when the injection port of the fuel injection valve is located at the top dead center as described in claim 4, It is characterized in that it is located between the top ring and the oil ring of the piston.

Further, in the in-cylinder fuel injection type four-cycle engine described in claims 1 to 4, as described in claim 5, the fuel injection valve directs the fuel toward the top wall of the combustion chamber. It is characterized in that it is arranged so as to jet.

Further, in the in-cylinder fuel injection type four-cycle engine described in claims 1 to 4, as described in claim 6, the fuel injection valve is an exhaust valve in a closed state. It is characterized in that it is arranged so as to inject fuel toward it.

Further, in the in-cylinder fuel injection type four-cycle engine described in claims 1 to 4, as described in claim 7, the fuel injection valve has a direction orthogonal to the axial direction of the cylinder hole. The fuel cell is arranged so as to inject fuel toward the inner wall of the opposing cylinder hole.

Further, in the in-cylinder fuel injection type four-cycle engine described in claims 1 to 4, as described in claim 8, the plurality of intake valves in which the fuel injection valve is opened are provided. It is characterized in that it is arranged so as to inject fuel toward between the valves.

Further, in the in-cylinder fuel injection four-cycle engine according to any one of claims 1 to 4, as described in claim 9, the fuel injection valve is directed toward at least one intake valve, It is characterized in that the injected fuel always collides with the valve regardless of the opening / closing position of the intake valve.

Further, in the in-cylinder fuel injection type four-cycle engine described in claim 4, the above-mentioned claim 10 is used.
As described above, the fuel injection valve is arranged downward so as to inject fuel toward the upper surface of the piston.

Further, in the in-cylinder fuel injection type four-cycle engine described in claim 4, the above-mentioned claim 11 is used.
The fuel injection valve is disposed downwardly so as to reflect the fuel toward the spark plug by injecting the fuel toward at least one of the valve recesses formed in the upper surface of the piston, as described in 1. It is characterized by that.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In-cylinder fuel injection type 4 of the present invention will now be described.
Each embodiment of the cycle engine will be described based on the drawings.

FIG. 1 shows a main part of a first embodiment of a cylinder fuel injection type four-cycle engine of the present invention. The cylinder head 2 and the cylinder block 3 of the four-cycle engine 1 have a gasket 4 interposed therebetween. A cylinder head cover (not shown) is connected to the upper surface side of the cylinder head 2, and a ceiling wall portion 6 of the combustion chamber is recessed on the lower surface thereof. A crankcase (not shown) is integrally installed below the cylinder block 3, and a cylinder hole 7 is provided above the crankcase.
Are formed.

A plurality of intake ports 12 and exhaust ports 13 are formed in the cylinder head 2 so that one ends of the cylinder head 2 are opened to the combustion chamber top wall portion 6 formed on the lower surface of the cylinder head 2. The spark plug 14 is installed so as to be located substantially in the center of the portion 6, and the intake valve 15 or the exhaust valve 16 is provided to open and close the combustion chamber openings of the intake port 12 and the exhaust port 13, respectively. It is installed at each room opening.

That is, as shown in FIG. 2, the combustion chamber top wall 6 on the lower surface of the cylinder head 2 has three combustion chamber openings 12a of the intake port 12 and two combustion chamber openings 13a of the exhaust port 13. Each of the spark plugs 1 is opened, and the spark plug 1 is provided at the substantially center of the combustion chamber top wall portion 6 surrounded by each combustion chamber opening portion.
Four discharge units 14a are provided, and the opening of each port is opened and closed by an intake valve 15 or an exhaust valve 16, respectively.

On the other hand, a piston 9 is slidably fitted in a cylinder hole 7 of the cylinder block 3, and the piston 9 is axially supported by a crankcase via a piston pin 10 and a connecting rod 11. It is connected to a crankshaft (not shown), and the combustion chamber 5 is defined by the cylinder hole 7, the upper surface of the piston 9 and the combustion chamber top wall portion 6.

As shown in FIG. 3, on the upper surface of the piston 9, a shallow recessed portion 9b is formed in the central portion excluding the peripheral flat upper end portion 9a, and each intake / exhaust valve 15,
The valve recesses 9c are provided at positions facing 16 respectively, and the injection port 2 of the fuel injection valve 20 described later is provided.
A partial recess 9d is formed at a position facing 1 in FIG.

Although not shown, the intake port 12
A throttle valve is installed in the intake passage upstream of the exhaust gas so that the amount of intake air can be controlled, and a catalyst for purifying exhaust gas is installed in the exhaust passage downstream of the exhaust port 13. Has been done.

In such a 5-valve 4-cycle engine, as shown in FIG. 4, the cylinder block 3 has a fuel injection valve 20 for injecting fuel into the combustion chamber 5.
However, when the piston 9 is located at the top dead center, the injection port 21 is located between the upper end 9a of the piston 9 and the top ring 9e, and the fuel injection direction of the fuel injection valve 20 is the top wall of the combustion chamber. 6 is attached to the valve mounting hole 19 formed on the exhaust side of the cylinder block 3 so as to be removable.

Although not shown in the drawings, the fuel injection valve 20 is pressurized and supplied with the fuel stored in the fuel tank by a fuel supply pump which is driven in conjunction with the rotation of the crankshaft of the engine. The injection start timing and injection time of the fuel supplied under pressure are set in advance according to the operating state by the control of the ECU (electronic control unit) based on the detection of the engine speed, the throttle opening, and other operating states of the engine. The fuel injection valve itself is not different from the fuel injection valve used in the conventional fuel injection type four-cycle engine.

According to the in-cylinder fuel injection type four-cycle engine having the above-mentioned structure, since the injection port 21 of the fuel injection valve 20 is provided on the cylinder block 3 side,
Unlike the case where the injection port 21 is provided on the cylinder head 2 side, it is not necessary to make the combustion chamber top wall 6 largely recessed,
Therefore, the increase in the volume of the combustion chamber can be suppressed, and the decrease in the compression ratio can be suppressed.

When the injection port 21 of the fuel injection valve 20 is provided in the vicinity of the joint surface with the cylinder head 2 (joint surface with the gasket 4), the strength of the cylinder block 3 at that portion is lowered. According to the above-mentioned configuration, since the injection port 21 is separated from the joint surface so as to overlap the piston 9 at the top dead center, it is possible to avoid such a decrease in strength of the cylinder block 3. it can.

Further, although the injection port 21 overlaps with the piston 9 at the top dead center, the cylinder hole 7
Since it is opened near the upper end of the engine, when injection is started during the intake stroke, such as when the load is high, the injection is started from the earliest possible timing to ensure that the fuel and intake air are sufficiently mixed. In order to allow mixed combustion, and when injection is started in the latter part of the compression stroke, such as when the load is low, start injection as close to the ignition timing as possible to perform stratified combustion while maintaining the stratified state. Therefore, the degree of freedom of the injection timing of the fuel injection valve 20 can be secured.

Further, in this embodiment, the fuel injection valve 20 is arranged so that the fuel injection direction is directed from the exhaust side to the combustion chamber top wall portion 6.
Are arranged, as shown in FIG. 5 and FIG.
Immediately after the piston 9 located at the top dead center starts descending and the intake stroke is started, the fuel injection valve 20 causes the injection port 21
By injecting the fuel in a wide range, the premixed combustion can be performed in a state where the intake air and the injected fuel are mixed for a sufficient time.

At that time, the flow of the intake air flowing into the cylinder collides with the flow of the injected fuel to promote atomization and vaporization, and the flow of the fuel flows from the exhaust side to the intake side. Therefore, the blow-through of the fuel is reduced, and the injected fuel does not hit the wall surfaces of the piston 9 and the cylinder hole 7, so that the generation of HC is suppressed.

Further, since the injection port 21 of the fuel injection valve 20 is located between the upper end portion 9a of the piston 9 and the top ring 9e at the time of the top dead center, the injection port 21 and the piston 9 are overloaded. Despite the wrapping, the cylinder can be sufficiently sealed by the top ring 9e, and the injection port 21 is located at the position of the top dead center at a position facing the injection port 21 on the upper surface of the piston 9. Since the recess 9d that partially overlaps with the piston 9 is partially formed, the injection of fuel is not obstructed by the piston 9 located near the top dead center, and the piston 9 for the injected fuel is
Adhesion to the will also be reduced.

Although the first embodiment of the present invention has been described above, the cylinder fuel injection type four-cycle engine of the present invention is not limited to the one having the specific structure as described above, but is located at the top dead center. Piston 9 and fuel injection valve 2 when
Other various embodiments are possible as long as the fuel injection valve 20 is installed on the cylinder block 3 side so as to overlap the injection port 21 of 0. The other embodiments of the present invention will be further described. In each of the following embodiments, the description of the parts having the same configurations and effects as those of the first embodiment will be omitted.

FIGS. 7 and 8 show a second embodiment of the present invention. In this embodiment, the fuel injection valve 2
0 is arranged on the intake side of the cylinder block 3 so that the fuel injection direction is toward the combustion chamber top wall portion 6.

According to such an embodiment, by injecting the fuel immediately after the start of the intake stroke, the in-cylinder flow due to the intake air can be further strengthened by the fuel injection flow, and a sufficient time and a strong force can be obtained. Premixed combustion can be performed in a state where the intake air and the injected fuel are sufficiently mixed by the in-cylinder flow, and the injected fuel can be stratified when the load is low, and the injection timing is near the top dead center. By delaying the delay time, the stratified charge combustion can be effectively performed.

Therefore, the lean burn operation can be stably performed, and since the injected fuel does not hit the wall surfaces of the piston 9 and the cylinder hole 7, the generation of HC is suppressed.

9 and 10 show a third embodiment of the present invention. In this embodiment, a fuel injection valve 20 for injecting fuel into two areas in a narrow range is provided with an intake air of a cylinder block 3. It is arranged on the side so that the injected fuel collides with the exhaust valves 16 in the closed state.

According to such an embodiment, the piston 9 located at the top dead center starts descending to start the intake stroke,
Immediately after the exhaust valve 16 is closed, the fuel injection valve 20
By injecting fuel from the injection port 21 toward the exhaust valve 16, the fuel collides with the heated exhaust valve 16.

Therefore, the premixed combustion is performed in a state where the atomization and vaporization of the fuel are promoted by the heat of the exhaust valve 16, and the injected fuel does not hit the wall surface of the piston 9 or the cylinder hole 7. Generation of HC will be suppressed.

11 and 12 show the fourth embodiment of the present invention. In this embodiment, the fuel injection valve 20 is directed so that the fuel injection direction is from right next to the inner walls of the cylinder hole 7 facing each other. , Are arranged so as to be orthogonal to the axial direction of the cylinder hole 7. Although the fuel injection valve 20 shown in the drawing is located on the intake side,
The position of may be anywhere on the entire circumference of the cylinder hole 7.

According to such an embodiment, the injected fuel does not directly contact the discharge portion 14a of the ignition plug 14, so that the fuel is less likely to smolder and the injected fuel travels a long distance. The fuel will be vaporized.

When the fuel is injected at an early timing after the intake stroke starts, the fuel is injected with the injection range narrowed and the fuel is injected at a late timing after the intake stroke starts. At times, by injecting the fuel in a state where the injection range is wide, it is possible to avoid the fuel from directly hitting the piston 9, and it is possible to reduce the HC.

13 and 14 show a fifth embodiment of the present invention. In this embodiment, the fuel is
The fuel injection valve 20 which injects into a narrow range in the direction is arranged on the intake side of the cylinder block 3 so as to respectively inject fuel between the intake valves 16 which are open in the intake stroke. In addition, the injection port 21 of the fuel injection valve 20 is opened so as to be located between the top ring 9e of the piston 9 and the oil ring 9f at the position of the top dead center.

According to such an embodiment, since the flow of intake air interferes between the opened intake valves 16 and the fuel is injected to a portion where the speed fluctuation is large (the flow velocity is largely disturbed), the fog is generated. As a result, the premixed combustion can be performed in a state where the intake air and the injected fuel are sufficiently mixed.

Further, since the injection port 21 of the fuel injection valve 20 is opened at a position between the top ring 9e of the piston 9 and the oil ring 9f at the position of the top dead center, the injection port 21 is opened with respect to the injection port 21. The oil from below does not enter, and the combustion pressure from the combustion chamber 5 is not applied.

Therefore, as compared with the case where the injection port 21 is opened so as to communicate with the combustion chamber 5 which has high temperature and high pressure, the fuel injection valve 20 is not required to have high durability and pressure resistance. The cost of the fuel injection valve 20 itself can be reduced.

FIG. 15 and FIG. 16 show a sixth embodiment of the present invention. In this embodiment, the fuel injection valve 20 is provided in the central position of each intake valve 16 as shown in FIG. As shown in 16 (A) to (C), even if the intake valve 16 is in any open / close position,
It is arranged on the intake side of the cylinder block 3 so that the injected fuel always collides with the intake valve 16.

According to this embodiment, when the fuel is injected during the intake stroke while the intake valve 16 is open, the opening timing of the intake valve 16 is delayed or the closing timing is advanced. At times, the injected fuel always collides with the moving intake valve 16.

For this reason, the opening / closing timing of the intake valve 16 is controlled by VVT (variable valve timing device) to early close at low load / low / medium speed and late close at high load / high speed, and at the intake stroke. In case of injecting fuel, intake valve 16 opened at high load and high speed
When the fuel is injected so that the fuel collides with the intake valve 16, the intake valve 16 is in a state of moving from the open state to the closed state at the time of low load and low medium speed.
Due to the collision of the fuel with the fuel, even when the in-cylinder flow is small at a low load and a low medium speed, the movement of the collision point due to the movement of the intake valve 16 can promote the diffusion of the fuel in the cylinder. .

FIG. 17 shows the seventh embodiment of the present invention. In this embodiment, the fuel injection valve 20 injects fuel toward the intake side of the cylinder block 3 toward the upper surface of the piston 9. It is placed downwards.

According to such an embodiment, as shown in FIG. 17, when the fuel is injected toward the upper surface of the piston 9 when the intake valve 16 is open during the intake stroke,
The injected fuel is reflected on the upper surface of the piston 9 and then collides with the flow of intake air, whereby atomization is promoted and premixed combustion can be performed in a state where the intake air and the injected fuel are sufficiently mixed. .

Further, when the fuel is injected toward the upper surface of the piston 9 while the intake valve 16 is closed in the compression stroke, the ascending force of the piston 9 and the fuel injection force of the fuel injection valve 20 correlate with each other. As a result, the injected fuel and the piston 9 collide more strongly and atomization is promoted. Therefore, even when the upper surface temperature of the piston 9 is low, such as when starting at a low temperature, the injected fuel is reflected while ensuring atomization of the fuel. By so doing, stratification of the injected fuel at low and medium speeds can be achieved to reduce the emission of unburned HC and to reduce HC at low temperature start.

FIG. 18 shows an eighth embodiment of the present invention. In this embodiment, the fuel injection valve 20 is provided on the intake side of the cylinder block 3 with a valve recess 9c (which is recessed in the upper surface of the piston 9). The intake valves 16 are arranged downward so as to inject fuel toward one of the intake valves 16 (corresponding to the valve located at the center).

According to such an embodiment, a special shape for reflecting the injected fuel is not newly provided on the upper surface of the piston 9, that is, such a special shape makes the shape of the combustion chamber 5 worse. Instead, it is possible to reflect the injected fuel toward the discharge portion 14a of the spark plug by utilizing the existing valve recess 9c.

As shown in FIG. 18, when the fuel is injected while the intake valve 16 is open during the intake stroke, the injected fuel is reflected and collides with the flow of intake air, resulting in atomization. The pre-mixed combustion can be performed in a state where the intake air and the injected fuel are sufficiently mixed with each other by being promoted, and when the fuel is injected while the intake valve 16 is closed in the compression stroke, low and medium speeds are achieved. Sometimes it is possible to effectively stratify the injected fuel, reduce the emission of unburned HC,
It is possible to improve fuel efficiency.

As in the seventh embodiment shown in FIG. 17 and the eighth embodiment shown in FIG. 18, the injection port 21 of the fuel injection valve 20 is at a lower position apart from the combustion chamber 5, that is, , Top ring 9e of piston 9 at the top dead center position
In the position between the oil ring 9f and the oil ring 9f, the fuel injection valve 20 is opened downward as compared to the case where the injection port 21 is opened in the combustion chamber 5 where the temperature and pressure are high. Since high durability and pressure resistance are not required,
The cost of the fuel injection valve 20 itself can be reduced, and since the injection port 21 of the fuel injection valve 20 is opened downward, the sagging of the fuel after the injection is injected into the injection port 21.
Since it is difficult to adhere to carbon, it is possible to reduce the adhesion of carbon to the portion.

[0057]

According to the in-cylinder fuel injection type four-cycle engine of the present invention as described above, while securing the strength in the vicinity of the cylinder head joint surface of the cylinder block,
Since the fuel injection valve can be installed on the cylinder block side, a large compression ratio can be achieved, and the fuel injection timing of the fuel injection valve can be sufficiently secured.

[Brief description of drawings]

FIG. 1 is a cross-sectional side view of essential parts showing a first embodiment of a cylinder fuel injection type four-cycle engine of the present invention.

FIG. 2 is a bottom view showing a combustion chamber top wall portion formed on the bottom surface of the cylinder head in the embodiment shown in FIG.

FIG. 3 is a top view showing the top surface of the piston in the embodiment shown in FIG.

FIG. 4 is an enlarged cross-sectional side view of essential parts showing the positional relationship between the piston top dead center position and the injection port of the fuel injection valve in the embodiment shown in FIG.

5 is an explanatory side view showing a fuel injection state from the fuel injection valve in the embodiment shown in FIG.

FIG. 6 is an explanatory plan view of the fuel injection state shown in FIG.

FIG. 7 is a side view showing a state of fuel injection from the fuel injection valve according to the second embodiment of the present invention.

FIG. 8 is an explanatory plan view of the fuel injection state shown in FIG.

FIG. 9 is a side view showing a fuel injection state from the fuel injection valve according to the third embodiment of the present invention.

10 is an explanatory plan view of the fuel injection state shown in FIG.

FIG. 11 is an explanatory side view showing a fuel injection state from the fuel injection valve according to the fourth embodiment of the present invention.

12 is an explanatory plan view of the fuel injection state shown in FIG.

FIG. 13 is an explanatory side view showing a fuel injection state from a fuel injection valve according to a fifth embodiment of the present invention.

FIG. 14 is an explanatory plan view of the fuel injection state shown in FIG.

FIG. 15 is an explanatory side view showing a fuel injection state from a fuel injection valve according to a sixth embodiment of the present invention.

FIG. 16 is an explanatory diagram showing a reflected state of each injected fuel when (A) the intake valve is closed, (B) the intake valve is half-open, and (C) the intake valve is fully open in the embodiment shown in FIG. 15.

FIG. 17 is a side view showing a fuel injection state from a fuel injection valve according to a seventh embodiment of the present invention.

FIG. 18 is an explanatory side view showing a fuel injection state from the fuel injection valve according to the eighth embodiment of the present invention.

[Explanation of symbols]

 1 Engine 2 Cylinder Head 5 Combustion Chamber 6 Combustion Chamber Top Wall 7 Cylinder Hole 9 Piston 9a (Piston) Top End 9c (Piston Top) Valve Recess 9d (Piston Top Piston) Recess 9e (Piston Top) Top ring 9f Oil ring (for piston) 12 Intake port 13 Exhaust port 14 Spark plug 14a Discharge part (for spark plug) 15 Intake valve 16 Exhaust valve 20 Fuel injection valve 21 Injection port

Front page continuation (72) Inventor Hiroyuki Miyako Take 2500, Shinkai, Iwata, Shizuoka Prefecture Yamaha Motor Co., Ltd.

Claims (11)

[Claims] 1. A cylinder block in which an intake port and an exhaust port opened and closed by a valve are opened and a discharge part of an ignition plug is arranged in a top wall of a combustion chamber formed on a lower surface of a cylinder head. A piston is slidably fitted into a cylinder hole formed in the cylinder head, and the cylinder head and the cylinder block are connected so that the combustion chamber is defined by the combustion chamber top wall portion, the cylinder hole, and the upper surface of the piston. In addition, in the in-cylinder fuel injection four-cycle engine in which a fuel injection valve for directly injecting fuel into the combustion chamber is installed, the piston and the injection port of the fuel injection valve when located at the top dead center are An in-cylinder fuel injection four-cycle engine, in which a fuel injection valve is installed on the cylinder block side so as to overlap. 2. The in-cylinder fuel injection according to claim 1, wherein the injection port of the fuel injection valve is located between the top end of the piston and the top ring at the top dead center. Formula 4-cycle engine. 3. The in-cylinder according to claim 2, wherein a concave portion that overlaps the injection port at a position of the top dead center is partially formed at a position facing the injection port on the upper surface of the piston. Fuel injection 4-cycle engine. 4. The in-cylinder fuel injection according to claim 1, wherein the injection port of the fuel injection valve is located between the top ring and the oil ring of the piston at the top dead center. Formula 4-cycle engine. 5. The in-cylinder fuel injection type four-cycle engine according to claim 1, wherein the fuel injection valve is arranged so as to inject fuel toward the top wall of the combustion chamber. 6. The in-cylinder fuel injection type 4 according to claim 1, wherein the fuel injection valve is arranged to inject fuel toward an exhaust valve in a closed state. Cycle engine. 7. The fuel injection valve according to claim 1, wherein the fuel injection valve is arranged so as to inject fuel toward the inner wall of the opposing cylinder hole in a direction orthogonal to the axial direction of the cylinder hole. The in-cylinder fuel injection type four-cycle engine described. 8. The in-cylinder according to claim 1, wherein the fuel injection valve is arranged so as to inject fuel toward between the plurality of intake valves which are in an open state. Fuel injection 4-cycle engine. 9. The fuel injection valve is arranged so that the injected fuel always collides with at least one intake valve regardless of the open / close position of the intake valve. 5. The method according to claim 1, wherein
The in-cylinder fuel injection four-cycle engine described in 1. 10. The in-cylinder fuel injection type four-cycle engine according to claim 4, wherein the fuel injection valve is arranged downward so as to inject fuel toward the upper surface of the piston. 11. The fuel injection valve is arranged downward so as to reflect the fuel toward the spark plug by injecting the fuel toward at least one of the valve recesses formed in the upper surface of the piston. The in-cylinder fuel injection type 4-cycle engine according to claim 4, wherein