JPH10274133A - Intercylinder injection type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly form an air-fuel ratio suitable for spark ignition at near an ignition plug, by arranging a fuel injection nozzle in a position where fuel is ejected toward a part near to the ignition plug while the opening part of an intake port to a combustion chamber is positioned in a part shifted from the center of a cylinder. SOLUTION: When the opening part of an intake port 6 to a combustion chamber 5 is positioned in a part shifted from the center point of a cylinder 4 to the outside, a tumble vortex applies turning motion that turns around an ignition plug 10. While, when a fuel injection nozzle 11 mounted on a cylinder head 2 is positioned in a part located adjacently to the intake port 6, and also a fuel injection direction from the fuel injection nozzle 11 is set slantly downward so as to be passed through a vicinity just under the ignition plug 10 and directed to a piston 3, ejected and supplied fuel is retained in a part near to the ignition plug 10, and an air-fuel ratio suitable for spark ignition can be certainly formed at near the ignition plug 10. Hereby, lean burn due to stratified intake air can be effectively achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called in-cylinder injection type internal combustion engine in which fuel for a cylinder is directly injected into the cylinder.

[0002]

2. Description of the Related Art In a recent internal combustion engine, for example, as described in JP-A-6-146886,
An intake port is opened downward into the combustion chamber at the top of the cylinder, and in the intake stroke due to the downward movement of the piston, the intake air flows into the cylinder from the intake port and flows downward from the intake port opening toward the piston. Later, a vertical tumble vortex is applied such that the top of the piston reverses upward and returns to the opening of the intake port again, and the fuel is directly injected to the tumble flow by the fuel injection nozzle. During the compression stroke due to the upward movement of the piston, stratified intake is performed in the vicinity of the spark plug to achieve an air-fuel ratio appropriate for spark ignition, achieving lean burn to reduce fuel consumption and reduce exhaust gas. Low pollution is being carried out.

[0003]

However, in this conventional in-cylinder injection type internal combustion engine, the fuel injected and supplied into the cylinder by the fuel injection nozzle is placed on the dumble vortex of the intake air in the cylinder. As a result, the fuel injected and supplied from the fuel injection nozzle into the cylinder is widely dispersed substantially at the same time as the injection and supply to the entire intake air in the cylinder. Cannot be achieved effectively.

An object of the present invention is to provide an in-cylinder injection type internal combustion engine that solves this problem.

[0005]

In order to achieve the above technical object, the present invention provides a cylinder having a piston reciprocating therein, a combustion chamber formed at the top of the cylinder, and an intake air provided in the combustion chamber. A port, an exhaust port, a spark plug provided at a substantially central portion of the combustion chamber, and a fuel injection nozzle for supplying fuel into the cylinder. The intake port is opened downward to the combustion chamber. do it,
For the intake from the intake port, a vertical tumble vortex is given such that it flows downward toward the piston, then reverses upward at the top surface of the piston and returns to the opening of the intake port again. In the in-cylinder injection type internal combustion engine, the opening of the intake port to the combustion chamber is located at a position shifted from the center of the cylinder when viewed from the direction of the cylinder axis, while the fuel injection nozzle is The fuel injection nozzle is provided at a position where fuel is injected toward a portion closer to the ignition plug in the inside of the tumble swirl. ".

[0006]

As described above, the opening of the intake port to the combustion chamber is located at a position shifted from the center of the cylinder when viewed from the direction of the cylinder axis. The tumble swirl is swirled around an ignition plug disposed at the center of the combustion chamber when viewed from the direction of.

[0007] Then, since the fuel from the fuel injection nozzle is injected and supplied to the inner side of the tumble vortex near the spark plug, the injected and supplied fuel immediately rides on the tumble vortex having the swirling motion. Without
The inner portion of the tumble swirl stays near the spark plug and is compressed toward the spark plug by the upward movement of the piston in this state, so that an air-fuel ratio appropriate for spark ignition is provided near the spark plug. Can be surely formed.

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

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment. 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 piston that reciprocates in the cylinder 4 of the cylinder block 1.

A combustion chamber 5 is formed in a recessed portion of the lower surface of the cylinder head 2 in the cylinder 4, and an intake valve 7 that opens downward with respect to the combustion chamber 5 is provided in the cylinder head 2. And an exhaust port 8 with an exhaust valve 9 for discharging exhaust gas from the combustion chamber 5 to the outside, and an ignition plug 10 is provided at a substantially central portion of the combustion chamber 5. It is screwed so that it is located.

In this case, the opening of the intake port 6 to the combustion chamber 5 is located at a position deviated outward from the center point of the cylinder 4 in a plan view of FIG. positioned. And reference numeral 11
2 shows a fuel injection nozzle mounted on the cylinder head 2. The fuel injection nozzle 11 is located at a position adjacent to the intake port 6 in a plan view of FIG. The direction of injection
It is set obliquely downward so as to pass to the piston 3 through the vicinity immediately below the ignition plug 10.

In this configuration, during the intake stroke due to the downward movement of the piston 3, the intake air sucked into the cylinder 4 from the intake port 6 flows downward from the opening of the intake port 6 toward the piston 3 and then flows downward. The tumble swirl in the vertical direction indicated by the arrow A is applied such that the top surface 3 turns upward and returns to the opening of the intake port 6 again.

In addition, when the intake port 6 is located at a position deviated outward from the center point of the cylinder 4 in a plan view of FIG. The tumble swirl indicated by is given a swirling motion such that the tumble swirl swirls around a spark plug 10 disposed substantially at the center of the combustion chamber 5 in a plan view of FIG. 2 viewed from the direction of the cylinder axis. Will be.

On the other hand, the fuel injection nozzle 11 mounted on the cylinder head 2 is located at a position adjacent to the intake port 6 in plan view of FIG. 2, and the direction of fuel injection from the fuel injection nozzle 11 is By being set obliquely downward so as to pass toward the piston 3 immediately below the ignition plug 10, the fuel from the fuel injection nozzle 11 can emit the fuel from the inside of the tumble vortex A having the swirling motion. Since the fuel is injected and supplied to the portion closer to 10, the injected and supplied fuel does not immediately ride on the tumble vortex A, but stays in the inner part of the tumble vortex near the spark plug. 3 is compressed toward the spark plug 10 by the upward movement of the spark plug 3. Therefore, an air-fuel ratio appropriate for spark ignition is ensured near the spark plug 10. It is possible to form the.

FIGS. 4 to 6 show a second embodiment. 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' reciprocates in a cylinder 4 'in the cylinder block 1'. Each of the pistons is shown. A combustion chamber 5 'is formed in the lower surface of the cylinder head 2' in a portion inside the cylinder 4 ', and the cylinder head 2' has a downwardly opening two-side opening with respect to the combustion chamber 5 '. One intake port 6 ', 6 "and two exhaust ports 8', 8" for discharging exhaust gas from the combustion chamber 5 to the outside are formed.
0 'is screwed so as to be located at a substantially central portion of the combustion chamber 5'.

In this case, the openings of the two intake ports 6 ', 6 "to the combustion chamber 5' are all formed in the cylinder 4 'when viewed from the axial direction of the cylinder 4'. ′ Is located at a position shifted outward from the center point of the second intake port 6 ″ of the first intake port 6 ′ and the second intake port 6 ″.
The intake control valve 12 is provided so as to close in an operation range where the intake air amount is small such as low rotation or low load and open in an operation range where the intake air amount is small.

Reference numeral 11 'denotes a fuel injection nozzle mounted on the cylinder block 1. The fuel injection nozzle 11' is located at a position adjacent to the one intake port 6 "in plan view of FIG. And the direction of fuel injection from the fuel injection nozzle 11 ′ is set obliquely upward so as to substantially approach the spark plug 10 ′ In this configuration, the amount of intake air such as low rotation or low load is set. In the operating range where the air flow is small, the intake air to the cylinder 4 is introduced from the first intake port 6 ', and the intake port of the first intake port 6' to the combustion chamber 5 'is ′, The air flows downward from the opening of the intake port 6 ′ toward the piston 3 ′ and then reverses upward at the top surface of the piston 3 ′, as in the first embodiment. The tumble vortex in the vertical direction indicated by arrow A 'is applied to return to the opening of the intake port 6' again, and the tumble vortex indicated by arrow A 'is seen from the direction of the cylinder axis. In the plan view of FIG. 5, a swirling motion is imparted such that the tumble swirl swirls around the spark plug 10 'disposed substantially at the center of the combustion chamber 5'.

On the other hand, the fuel injection nozzle 11 'mounted on the cylinder block 1' is located at a position adjacent to the one intake port 6 "in a plan view of FIG.
By setting the direction of the fuel injection from the fuel injection nozzle 11 ′ obliquely upward so as to be substantially toward the ignition plug 10 ′, the fuel from the fuel injection nozzle 11 ′
Since the fuel is injected and supplied to the portion of the inner side of the tumble swirl A 'having the swirling motion near the ignition plug 10', the injected and supplied fuel does not immediately get on the tumble swirl A 'and Since the piston 3 'is compressed toward the spark plug 10' by the upward movement of the piston 3 'in this state, it stays at the portion near the spark plug in the inside of the vortex, so that suction such as low rotation or low load is performed. In the operating range where the amount of air is small, a rich air-fuel ratio can be reliably formed near the ignition plug 10 ', as in the first embodiment.

In the second embodiment, in an operating range where the amount of intake air is large, such as high rotation or high load, the intake control valve 12 in the second intake port 6 ″ is opened, The intake air to the cylinder 4 can be introduced simultaneously from both intake ports 6 'and 6 ", so that the intake resistance is prevented from increasing.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing a first embodiment of the present invention.

FIG. 2 is a plan sectional view taken along line II-II of FIG.

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

FIG. 4 is a longitudinal sectional front view showing a second embodiment of the present invention.

FIG. 5 is a plan sectional view taken along line VV of FIG. 4;

FIG. 6 is a sectional view taken along line VI-VI of FIG.

[Explanation of symbols]

 1, 1 'Cylinder block 2, 2' Cylinder head 3, 3 'Piston 4, 4' Cylinder 5, 5 'Combustion chamber 6, 6' Intake port 10, 10 'Spark plug 11, 11' Fuel injection nozzle A, A ′ Tumble vortex

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02B 31/02 F02B 31/02 Z F02M 69/04 F02M 69/04 P

Claims (1)

[Claims] A cylinder in which a piston reciprocates;
A combustion chamber formed at the top of the cylinder, an intake port and an exhaust port provided in the combustion chamber, a spark plug provided at a substantially central portion in the combustion chamber, and fuel is injected and supplied into the cylinder. A fuel injection nozzle, the intake port is opened downward into the combustion chamber, and flows downward toward the piston with respect to intake air from the intake port, and then reverses upward at the top surface of the piston and again. In a direct injection internal combustion engine configured to impart a vertical tumble vortex that returns to the opening of the intake port, the opening to the combustion chamber at the intake port is viewed from the direction of the cylinder axis. While the fuel injection nozzle is located at a position shifted from the center of the cylinder, the fuel from the fuel injection nozzle is moved to the point on the inside of the tumble vortex. An in-cylinder injection internal combustion engine provided at a position where fuel is injected toward a portion close to a fire hydrant.