JPS61201826A - Intake device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the combustion stability of an internal-combustion engine by forming a siamese shape of intake sections for light and heavy loads, and providing a closing valve for a heavy load side at the junction of the above suction sections and arranging a fuel injection valve pointing to the center of both the intake sections. CONSTITUTION:A low speed suction port 30A and a high speed suction port 30B are arranged opposite to each other with a partition 30D at the center of both the suction ports to be formed into a siamese shape. Their junction 30C is provided with an suction control valve 31 to close the high speed port 30B at low speed running and a fuel injection valve 33 to inject fuel toward the partition 30D mounted at the center of both the ports. An intake being up a throttle valve 1 is guided through a tube 38 to be perpendicularly blowed to the above fuel jet. When the opening of the throttle valve 1 is narrow, the negative pressure of the intake closes the suction control valve 31, and causes a strong suction jet to blow out of the tube 38. Thus the fuel jet is turned toward the low speed port 30A, and violently swirled with the improved atomization of the fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an intake system for an internal combustion engine, and particularly to one in which a Siamese-structured intake port is communicated with a combustion chamber.

(Prior art) Since combustion tends to deteriorate when the engine load is low, an intake control valve is provided midway in the intake passage downstream of the intake throttle valve to open and separate the intake passage. A cutout in a part of this intake control valve keeps it fully closed! Various devices have been proposed that improve combustion by introducing intake air only through a portion or a gap provided around the intake control valve and increasing the intake air flow velocity to generate a strong swirl within the combustion chamber.

For example, there is a beat tra as shown in FIG. 10 (see Japanese Patent Application Laid-open No. 82523/1983). To explain this, the intake passage from the manifold collector section 2 downstream of the intake throttle valve 1 is independently branched into two intake passages 3.4 that open into the combustion chamber 5, and one intake passage 4 is provided with an intake passage that responds to the engine load. A control valve 6 is provided, and a fuel injection valve 7 whose injection amount is controlled according to the intake air flow rate is provided in the other intake passage 3. Note that 8 A and 8 B are intake valves, and 9 A and 9 I3 are exhaust valves.

Therefore, in the high load range, the opening operation of the intake control valve 6 causes
Both intake passages 3 and 4 are opened, and the flow rate of intake air supplied to the combustion chamber 5 increases, increasing charging efficiency.
A large engine output corresponding to the load at this time can be obtained.

On the other hand, in a low load range, the intake control valve 6 is fully closed, and intake air is supplied to the combustion chamber 5 through only one intake passage 3. For this reason, the flow path is narrowed, so the intake air flow rate increases, and this - intake air flow rate is used to increase the combustion chamber.
A strong swirl is generated within the combustion chamber, improving combustion efficiency. This improves fuel efficiency in this driving range.

(Problem to be solved by the invention, α) In such a device, the intake passage downstream of the manifold collector portion 2 is 2. It is independent from the system and the fuel injection valve 7
is disposed in one intake passage 3, so that only air flows into the combustion chamber 5 from the other intake passage 4 during a high-pressure operation when the intake control valve 6 is opened. For this reason, it is difficult to form a uniform air-fuel mixture within the combustion chamber 5, resulting in a non-uniform air-fuel mixture that is partially rich. When such an uneven air-fuel mixture is ignited, the partially rich air-fuel mixture has poor combustion properties, resulting in a deterioration of combustion efficiency, resulting in engine output compared to when fuel is distributed and supplied from both intake ports. This results in a decrease in the amount of unburned HC and an increase in unburned HC, and also makes knocking more likely to occur.

This invention was made by focusing on these conventional problems, and provides an intake system that improves combustion efficiency based on strong swirl at low loads, and at the same time homogenizes the air-fuel mixture at high loads. The purpose is to provide

(Means for solving the problem) The present invention provides two ports, a low load side port section and a high load side port section.
An intake port of Siamese groove structure having two port sections, an intake control valve that is interposed in the gathering section of the intake ports and closes the intake port according to the engine load, and an intake control valve that is oriented near the center of the partition wall between the port sections. a fuel injection valve that injects fuel;
An auxiliary air passage that opens near the injection hole of the injection valve and deflects the injection direction of the injected fuel is provided.

(Function) With this configuration, when the load is high, fuel is injected from the fuel injection valve toward the center of the partition wall between the port sections, so the injected fuel is evenly distributed to the two port sections, and this injection The fuel is quickly mixed with the intake air whose intake flow rate has increased by opening the intake control valve, and the fuel is supplied to the combustion chamber. Therefore, unlike injected fuel that is supplied from only one intake passage, it is easy to form a uniform air-fuel mixture in the combustion chamber, and this improvement in combustion properties improves engine output and fuel efficiency, as well as reduces exhaust emissions. It is possible to reduce the

In addition, when the intake control valve closes during low load, the intake air flows through a notch provided in a part of the control valve or a gap around the control valve, so the intake flow rate increases. A large pressure difference occurs before and after the intake control valve, and air is jetted from an auxiliary air passage opened near the injection hole of the injection valve in response to this pressure difference or the branched flow.

On the other hand, even in this operating range, the fuel is evenly distributed and injected from the fuel injection valve toward the center of the partition wall between the ports, but due to this jet of air, the injection direction of the injected fuel is directed to the low-load side port. Most of the injected fuel flows into the combustion chamber from the low-load side port as intake air with increased flow velocity.

For this reason, the small amount of fuel corresponding to this operating range is not dispersed (concentrated in the low-load side port section, and this concentrated injected fuel and fast intake air create a strong swirl in the combustion chamber, resulting in poor combustion properties. improve.

Combustion stability or engine stability is achieved by improving combustion properties.

(Embodiment) FIG. 1 is a sectional view of a main part of a first embodiment of the third aspect of the invention, and FIG. 2 is a partially sectional plan view of a cylinder head portion. In the figure, 20 is the engine body, 21 is the cylinder block, 22 is the cylinder head, 23 is the combustion chamber, and 25 is the intake manifold 2.
Intake passage formed by 4 etc., 26 is an exhaust passage, 27
A, 27B are intake valves, 28 is an exhaust valve, and 29 is a spark plug.

An intake port 30 having a Siamese structure and having two port sections, a low load side port section 30A and a high load side port section 30B, is formed in the sill head 22 and communicates with the combustion chamber 23.

An intake control valve 31 is interposed in the intake passage 25 near the gathering portion 30C of the intake port 30, and the intake control valve 31 has a cutout portion 31A formed at its periphery on the low-load side port portion 30A side. . The intake control valve 31 opens in response to intake negative pressure (engine load). Note that 32 is a seven-diamond ram actuator that operates the intake control valve 31 using the intake negative pressure upstream of the intake control valve 31 as the operating negative pressure.

33 is a hole 3 for mounting at a position near the downstream of the intake control valve 31.
The fuel injection valve is fixed at the intake bow 30 and is fixed at the intake bow 30, with the injection valve shaft oriented near the center 30D of the partition wall between the two port portions 30A and 30B. Therefore, the fuel spray from the injection valve 33 is dispersed in a conical shape, so that it is evenly distributed and supplied toward the two port sections 30A and 30B.

An air ring 35 is press-fitted near the injection hole of each injection valve 33 formed in the intake manifold 24 .

The air ring 35 has an air groove 35A on the outer periphery as shown in FIG.
is formed, and an air injection hole 35B penetrating the inner periphery of the air ring 35 is passed through the air groove 35A. For this reason,
In the press-fitted state, the inner periphery of the air ring 35 is formed as a nozzle hole 35C, and an air nozzle hole 35B communicating with the air groove 35A opens in the nozzle hole 35C.

Reference numeral 37 denotes a communication passage formed in the intake manifold 24 passing between the cylinders, and this communication passage 37 communicates with the air groove 35A for each cylinder. 38 is a passage that communicates this communication passage 37 with the intake passage 25 upstream of the intake throttle valve 1.

In this way, an auxiliary air passage that bypasses the intake control valve 31 and opens near the nozzle of the injection valve 33 is formed from the passage 38, the communication passage 37, the air groove 35A, and the air injection hole 35B.

Therefore, when the intake control valve 31 closes under low load, a large negative pressure is generated downstream of the intake control valve 31, and the intake throttle valve responds to the differential pressure between this negative pressure and the atmospheric pressure upstream of the intake throttle valve 1. 1
The upstream air flows from the air injection hole 35B through the auxiliary air passage almost perpendicularly to the injection valve axis. In this case, when fuel is injected from the injection valve 33, a jet of air collides with the fuel spray, and the fuel spray is deflected toward the low-load side port portion 30A.

The direction and degree of this deflection are determined by the angle, cross-sectional area, etc. of the air nozzle hole 25B with respect to the nozzle hole 35C, but in this example, it is approximately perpendicular to the fuel spray, and the fuel spray after deflection is low. It has been positioned so that it faces the load side port) 8IS30A.

To describe the effect of such a configuration, in a low-load operating state, the intake control valve 31 closes in response to a large suction negative pressure generated downstream of the intake throttle valve 1 (the illustrated state shows a fully closed state). ). Therefore, the intake air flows through the intake port 3'0 through the notch 31A formed on the side of the low load side port 30A.
However, most of the intake air increases the flow velocity by the notch 31A that narrows the flow path area and flows into the combustion chamber 23 from the low-load side port 30A, so a strong swirl is generated in the combustion chamber 23.

On the other hand, the fuel spray from the injection valve 33 flows through the two port portions 30.
A and 30B, but due to the differential pressure between the upstream of the intake throttle valve 1 and the downstream of the intake control valve 31, the air upstream of the intake throttle valve 1 is injected into the passage 38, the communication passage 37, and the air groove 3.
Air nozzle hole 35B opens near nozzle hole 35C via 5A
The jet flows from the injection valve 33 in a direction substantially perpendicular to the injection direction of the injection valve 33.

This jet of air causes the fuel injection 71 as shown in Pt53 diagram.
39 is deflected, and most of the intake air flows into the combustion chamber 23 from the low-load side port portion 30A with the increased flow velocity, and at the same time, it rises to this air jet, promoting atomization of the sprayed fuel and mixing with the air. As a result, even under operating conditions where fuel mixture vaporization is difficult, such as at low temperatures, this jet air actively promotes mixture vaporization, resulting in good mixing of fuel and air within the combustion chamber 23. In addition, the strong swirl caused by the closing of the intake control valve 31 significantly improves combustion.

In this way, a mixture with improved combustion properties improves the combustion speed and increases combustion stability, so even engines that perform lean mixture combustion or engines that recirculate a large amount of exhaust gas at low loads can achieve stable combustion. It is possible to achieve improvements in fuel efficiency and exhaust emissions.

On the other hand, in a high load state, the intake control valve 31 opens in response to the opening of the intake throttle valve 1 (the state shown in FIG. 2), so the difference between the upstream of the intake throttle valve 1 and the downstream of the intake control valve 31 is The pressure is removed and the jet of air through the auxiliary air passage stops.

For this reason, as shown in FIG. 4, the fuel injection 7 from the injection valve 33
339 is not deflected, so the fuel spray is dispersed in a conical manner through the two port portions 30A.

30B, and as in a normal Siamese two-intake valve engine without an intake control valve 31, air and fuel are evenly taken in when the two intake valves 27A and 27B are opened.

As a result, unlike conventional examples where fuel is supplied from only one intake port and a partially rich mixture is formed, the mixture is formed uniformly.
This improves combustion efficiency, improves the fuel output and reduces exhaust emissions, and also improves knock resistance.

Note that opening the intake control valve 31 increases the intake air filling efficiency, which further contributes to improving combustion efficiency and further enhances effects such as high output, low exhaust emissions, and low fuel consumption.

In addition, if the intake port 30 has a Siamese structure,
Unlike the case where the intake passage 25 downstream of the intake throttle valve 1 is independently branched and communicated with the combustion chamber 23, it can be significantly simplified, and therefore productivity, yield, and cost can be significantly improved.

＠S figure is a sectional view of a main part of the second embodiment of the present invention, and FIG. 6 is a view taken in the direction of arrow A in FIG. 155.

In this example, the communication passage 37 constituting the auxiliary air passage, the installation of the injection valve 33, the hole 34, the injection hole 42 of the injection 033, and the intake passage portion in which the intake control valve 31 are installed are integrated into the intake manifold 24. The air injection holes 41 are formed as a separate part of the spacer 40 instead of being formed, and the air injection holes 41 are formed by drilling instead of forming the air injection holes with an air ring. For this reason, in the case where the air ring is press-fitted, high manufacturing precision is required for the dimensions of this press-fitting part, but in this example, the air nozzle hole 41 can be machined.
Accuracy control becomes easier. Note that 43 is a retainer for fixing the injection valve 33.

In this example, in addition to the effects of the first embodiment, productivity is improved due to ease of accuracy control.

FIG. 7 is a sectional view of a main part of a third embodiment of the present invention, FIG. 8 is a plan view of a cylinder head of this embodiment, and FIG. 9 is a diagram of a cylinder head of a fourth embodiment of this invention. FIG.

In the third embodiment, a notch is not provided in a part of the intake control valve 50, but in the fully closed position (as shown in FIG. 7), the entire circumference of the intake control valve 50 and the intake passage wall 25A are It is something that has a gap in darkness.

Further, the auxiliary air passage is formed by a bypass passage 51 that bypasses the intake control valve 50. That is, one end of the bypass passage 51 opens near the nozzle hole 52 of the injection valve 33, and the opening direction is formed obliquely with respect to the injection valve axis, oriented toward the low-load side bow)g30A. The other end is communicated not with the upstream side of the intake throttle valve but with the upstream side of this intake control valve 50.

Note that this example is applied to a four-valve type Isoseki.

on the other hand,! In the @4 embodiment, the intake control valve 50 and bypass passage 51 of the third embodiment are replaced by two intake valves 60A with different valve diameters,
This is applied to a 3-valve Isoseki with 60 I3.

These third and fourth embodiments also provide the same effects as the first embodiment.

(Effects of the Invention) This invention has a Siamese structure intake port having two port parts, a low-load side port part and a high-load side port part, and an intake port that is interposed in the gathering part of the intake ports and An intake control valve that opens and closes the intake port, a fuel injection valve that injects fuel toward the center of the partition between the ports, and an auxiliary air passage that opens near the injection hole of the injection valve and deflects the injection direction of the injected fuel. As a result, at high loads, evenly distributed injection toward both ports enables the formation of a uniform air-fuel mixture in the combustion chamber, resulting in improvements in engine output, fuel efficiency, and knock resistance due to improved combustion properties. improvement and reduction of exhaust emissions can be achieved.

In addition, at low loads, air is jetted from the auxiliary air passage opened near the nozzle hole of the injection valve in response to the large pressure difference before and after the intake control valve and the branched flow of intake air, and the direction of the injection force of the injected fuel is shifted to the low load side. When this fuel is deflected to the port and flows into the combustion chamber with a high intake flow velocity, a strong swirl is generated, and this improvement in combustion properties improves combustion stability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a first embodiment of the present invention, FIG. 2 is a partially sectional plan view of a shilling head portion of this embodiment, and FIG.
4 are explanatory diagrams showing the state of fuel spray during low load and high load, respectively, in this embodiment. FIG. 5 is a sectional view of a main part of a second embodiment of the present invention, and FIG. 6 is a view taken in the direction of arrow A in FIG. FIG. 7 is a sectional view of a main part of a third embodiment of the present invention, and FIG. 8 is a plan view of a shilling head portion of this embodiment. FIG. 9 is a plan view of a shilling head portion according to a fourth embodiment of the present invention. FIG. 10 is a schematic diagram of the US-based equipment. 1... Intake throttle valve, 20... Engine body, 22...
Schilling hand, 23... Combustion chamber, 24... Intake manifold, 25... Intake passage, 27A, 27B...
・Intake valve, 28.28A, 28B...Exhaust valve, 30・
...Intake port, 3OA...Low load side port section, 30
B...High load side port part, 30C...Collection part, 31
...Intake control valve, 31A...Notch, 32...
Dia 7 ram actuator, 33... fuel injection valve,
34... Mounting hole, 35... Air ring, 35A
...Air groove, 35I3...Air nozzle hole, 35C...
Nozzle hole of injection valve, 37... Communication passage, 38... Passage, 3
9... Fuel spray, 40... Spacer, 41... Air injection hole, 42... Nozzle hole of injection valve, 43... Retainer, 50... Intake control valve, 51... Bypass aisle, 5
2... Nozzle hole of injection valve, 60 A, 60 B... Intake valve. @Figure 1. 30A・--EC'@pl Noi lj'l 7r
F-) i30C-・-1 old part Fig. 5 Fig. 6 Fig. 2 Fig. 8

Claims (1)

[Claims] an intake port with a Siamese structure having two port sections, a low load side port section and a high load side port section; an intake control valve that is interposed in the gathering section of the intake ports and opens and closes the intake port according to the engine load; An internal combustion engine characterized by having a fuel injection valve that injects fuel toward the center of a partition wall between ports, and an auxiliary air passage that opens near the injection hole of the injection valve and deflects the injection direction of the injected fuel. Engine intake system.