JPH10159568A - In-cylinder injection type internal combustion engine structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an air-fuel ratio in the vicinity of an ignition plug in a rich condition more than the other part, and realize lean burning by stratified intake surely by arranging a fuel injector on a part between two exhaust ports holding a longitudinal center so as to direct injection fuel to a part nearly just below an intake port. SOLUTION: When a piston 3 exceeds a top dead point, a recessed part 3a as combustion space is formed on the top surface thereof, and a fuel injector 12 is arranged by drilling a fuel feed port 14 on one side held a longitudinal center line 8 in a cylinder head 2. In this case, more preferably the fuel injector 12 is arranged on a part between both exhaust ports 7a, and 7b holding the longitudinal center line 8 so as to inject fuel toward a part nearly just below intake ports 6a, 6b. Injection fuel is blown from the fuel injector 12 toward a part returned to the opening part of both intake ports 6a, 6b in tumble flow 15a, 15b, and thereby, an air-fuel ratio in the vicinity of an ignition plug 11 makes in a rich condition more than the other part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a direct injection internal combustion engine in which fuel for a cylinder is directly injected into a cylinder of the cylinder while air is mixed with the fuel. It is.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open No. 6-14688 as prior art.
Japanese Patent Application Laid-Open Publication No. 6-106, discloses a cylinder injection type internal combustion engine of this type, of a cylinder head fastened to the upper surface of a cylinder block having a cylinder, a longitudinal center line extending in the direction of the crankshaft through the center of the cylinder in plan view. Two intake ports communicating with the combustion chambers on the lower surface of the cylinder head on one side, and two exhaust ports communicating with the combustion chambers on the lower surface of the cylinder head on the other side. By providing an intake valve at the opening into the cylinder, and an exhaust valve at the opening of the two intake ports into the cylinder, and introducing the intake air from the air cleaner into the cylinder through the two intake ports, While forming two tumble flows (vertical swirl flow) in the cylinder, an ignition plug is arranged at a substantially central part of the cylinder in the cylinder head. Further, a fuel supply port is formed in a portion between the intake ports of the cylinder head, and a fuel injector mixed with air is provided by providing a fuel injector of an aerated fuel injection type in the fuel supply port, It has been proposed to provide it so as to squirt toward a part between the two tumble flows.

[0003]

However, in this prior art, a fuel injector of the aerated fuel injection type is provided at a portion between both intake ports, so that the fuel injector is combined with air. The fuel injected immediately into the tumble flow immediately flows into the two tumble flows, causing the fuel to be widely dispersed.Therefore, fuel near the spark plug cannot be collected, and lean burn due to stratified intake is ensured. There was a problem that it could not be achieved.

An object of the present invention is to provide a structure of a cylinder injection type internal combustion engine which solves this problem.

[0005]

SUMMARY OF THE INVENTION In order to achieve this technical object, the present invention provides a cylinder head having a cylinder block fastened to the upper surface of a cylinder block having a cylinder through a center of the cylinder in a plan view. Two intake ports communicating with the combustion chamber on the lower surface of the cylinder head on one side with a longitudinal center line extending in the
Similarly, two exhaust ports communicating with the combustion chamber on the lower surface of the cylinder head are respectively formed, and an ignition plug is disposed at a substantially central portion of the cylinder head in the combustion chamber,
Furthermore, in the cylinder head, in a cylinder injection type internal combustion engine in which a fuel injector of an aerobic fuel injection type is provided, the fuel injector is disposed at a portion between the two exhaust ports on the other side with respect to the longitudinal center. The fuel injected from the fuel injector is provided so as to be directed to a position substantially directly below both intake ports. ".

[0006]

In this configuration, during the intake stroke due to the downward movement of the piston, intake air is introduced from both intake ports into the cylinder, so that the opening of both intake ports to the combustion chamber is formed in the cylinder. Starting at the bottom of the exhaust port, flows downwards below the two exhaust ports, and then reverses upward at the top of the piston and returns to the openings of the intake ports to the combustion chambers. The fuel injected together with air from the fuel injector is mixed with the two tumble flows.

In this case, as described above, according to the present invention, the fuel injected from the fuel injector into the two intake ports is provided between the two exhaust ports on the other side of the longitudinal center. By being provided so as to be directed to a position substantially immediately below, the injected fuel from the fuel injector crosses a portion where the flow velocity near the opening to the combustion chamber of both intake ports in the two tumble flows is high, In this case, the two tumble flows have a form in which they are turned upside down and hit a portion that returns to the openings of both intake ports.

That is, when the flow rate of the fuel injected from the fuel injector traverses a portion of the tumble flow where the flow velocity near the opening to the combustion chamber of both intake ports is high, the flow velocity is reduced. In a state in which the flow velocity is reduced, it will blow against the portion of both tumble flows that returns to the openings of both intake ports,
The injected fuel that has blown to this portion is mainly transmitted to the portion of the two tumble flows that returns to the openings of the intake ports, in other words, to the ignition plug that is disposed substantially at the center of the combustion chamber in the two tumble flows. Since the air-fuel ratio is mixed in the near portion, the air-fuel ratio in the vicinity of the ignition plug can be made richer than the other portions.

Therefore, according to the present invention, there is an effect that the lean burn by the stratified intake can be surely achieved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In this figure, reference numeral 1 denotes a cylinder block, reference numeral 2 denotes a cylinder head fastened to the upper surface of the cylinder block 1, and reference numeral 3 denotes a cylinder head.
Represents a piston that reciprocates in the cylinder 4 of the cylinder block 1, and a combustion chamber 5 is formed in a recess in the cylinder 4 on the lower surface of the cylinder head 2. Also, on the top surface of the piston 3,
When the piston 3 moves up to the top dead center, a substantially hemispherical recess 3 a is formed so as to form a substantially spherical combustion space with the combustion chamber 5.

Reference numerals 6a and 6b denote a pair of intake ports to the combustion chamber 5, and reference numerals 7a and 7b denote a pair of exhaust ports from the combustion chamber 5, respectively.
a and 6b are located on one side with a longitudinal center line 8 extending in parallel with a crankshaft (not shown) passing through the center of the cylinder 4 in plan view, and the lower end thereof is inside the combustion chamber 5 and the other end thereof. The two exhaust ports 7a and 7b are integrally formed so as to open on one side surface 2a of the cylinder head 2, and the two exhaust ports 7a and 7b are provided on the other side with the longitudinal center line 8 therebetween in a plan view. Are formed in the combustion chamber 5 such that the other ends are united and open to the other side surface 2b of the cylinder head 2 respectively.

At the openings of the two intake ports 6a, 6b into the combustion chamber 5, intake valves 9a, 9b are provided. At the openings of the two exhaust ports 7a, 7b into the combustion chamber 5, exhaust valves are provided. 10a and 10b are provided respectively. An ignition plug 11 is mounted on the cylinder head 2 such that an electrode portion of the ignition plug 11 looks substantially at the center in the combustion chamber 5.

Further, a fuel supply port 14 is formed on the other side of the cylinder head 2 with respect to the longitudinal center line 8 and between the exhaust ports 7a and 7b. The supply port 14 is provided with a fuel injector 12 of the aerated fuel injection type (injecting a mixture of fuel and air), and the fuel is injected from the fuel injector 12 together with the air into the two intake ports 6a, 6b. It is configured to squirt obliquely downward toward a portion substantially directly below.

In this configuration, during the intake stroke due to the downward movement of the piston 4, the intake air is introduced into the cylinder 3 from the two intake ports 6a and 6b, as shown by arrows 15a and 15b in the drawing. Both intake ports 6
a, 6b starting from the opening to the combustion chamber 5, flowing downwardly below the exhaust ports 7a, 7b, and then reversing upward at the recess 3a on the top surface of the piston 3 to reopen the intake ports again. Two tumble flows, which return to the opening of the combustion chamber 5 of 6a and 6b, are generated.
The fuel injected together with air from the fuel injector 12 is mixed with the fuel cells a and 15b.

In this case, as described above, the fuel injected from the fuel injector 12 is supplied to the portion between the exhaust ports 7a and 7b on the other side of the longitudinal center line 8 with the fuel injector 12 interposed therebetween. The fuel injected from the fuel injector 12 is provided so as to be ejected obliquely downward toward a position substantially directly below the intake ports 6a and 6b.
b, after traversing a portion where the flow velocity near the opening to the combustion chamber 5 of both the intake ports 6a and 6b is high, the two tumble flows 15a and 15b are reversed upward to open the two intake ports 6a and 6b. It will take the form of hitting the part returning to the part.

That is, when the fuel injected from the fuel injector 12 crosses the portion of the tumble flows 15a and 15b where the flow velocity near the opening of the intake ports 6a and 6b to the combustion chamber 5 is high, the fuel flows therefrom. When the flow velocity is reduced, the two intake ports 6a and 6b of the tumble flows 15a and 15b are reduced in a state where the flow velocity is reduced.
Of the tumble flows 15a, 15b.
Since it is mixed with the portion that returns to the opening of a, 6b, in other words, the portion of the two tumble flows 15a, 15b that is close to the spark plug 11 that is disposed substantially at the center of the combustion chamber 5, the ignition is performed. The air-fuel ratio in the vicinity of the plug 11 can be made richer than other portions.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view of an embodiment of the present invention.
It is I sectional drawing.

FIG. 2 is a II-II bottom view of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder head 3 Cylinder 4 Piston 5 Combustion chamber 6a, 6b Intake port 7a, 7b Exhaust port 8 Longitudinal center line 9a, 9b Intake valve 10a, 10b Exhaust valve 11 Spark plug 12 Fuel injector 14 Fuel supply port 15a, 15b Tumble flow

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02M 61/14 310 F02M 61/14 310S 69/04 69/04 Z

Claims (1)

[Claims] 1. A cylinder head fastened to an upper surface of a cylinder block having a cylinder, the cylinder head lower surface being disposed on one side with a longitudinal center line extending in the direction of a crankshaft passing through the center of the cylinder in plan view. On the other side, two intake ports communicating with the combustion chamber of the cylinder head, and two exhaust ports communicating with the combustion chamber on the lower surface of the cylinder head are formed respectively. Arrange the spark plug, and
An in-cylinder injection-type internal combustion engine in which an aerated fuel injection type fuel injector is provided in the cylinder head, wherein the fuel injector is provided at a position between the two exhaust ports on the other side of the longitudinal center. A structure of an in-cylinder injection type internal combustion engine, wherein fuel injected from an injector is provided so as to go to a position substantially directly below both intake ports.