JPS59115465A - Intake passage device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent smoldering of a spark plug and deterioration in fuel consumption and exhaust composition in a specific cylinder, by arranging a cylindrical member so as to inject fuel into a passage inside this cylindrical member. CONSTITUTION:Injection fuel, being annularly injected toward the internal wall surface 17a of a cylindrical member 17, is mixed with intake air flowing through an internal passage 18, and a rich mixture is generated in this passage 18. While only intake air is allowed to flow through an external passage 19, and this intake air flows together and mixes with the rich mixture in an intake passage 12 in the downstream from the cylindrical member 17, thus generating a mixture of prescribed air-fuel ratio. On account of these results, the intake air flowing through the external passage 19 never allows fuel to adhere in a liquid state to an internal wall surface of the intake passage 12 in the downstream side of the cylindrical member 17. Further the injection fuel flows toward the internal wall surface 17a because a fuel injection valve 25 is arranged on an axial line of the intake passage 12, and never adheres to the internal wall surface of a throttle body 21 of the external passage 19.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake path device for an internal combustion engine, and more particularly to an intake path device for an internal combustion engine that is provided with a single-point injection device upstream of a throttle valve.

A single point injection system (SPI), also called a central injection system, injects fuel (gasoline) at one point in the intake pipe that communicates with each cylinder. The manufacturing cost can be reduced compared to a method (MPI) in which fuel is injected from an injection valve for each cylinder. Depending on the injection position, single-point injection devices include those that inject upstream of the throttle valve and those that inject downstream, similar to carburetors.In devices that inject upstream of the throttle valve, the injected fuel generally reaches the throttle valve. It is said that collision will result in better atomization of fuel and therefore better distribution to each cylinder.

As an intake path device for an internal combustion engine that injects fuel upstream of this throttle valve, conventionally, for example, U.S. Pat. No. 4,186,7
The one disclosed in the specification of No. 08 is known. In FIG. 1, 1 is a throttle body (intake pipe main body), and this throttle body 1 has an intake passage 2 formed therein.

Reference numeral 3 denotes a throttle valve provided in the intake passage 2, and a fuel injection valve 4 is disposed in the intake passage 2 upstream of the throttle valve 3. This fuel injection valve 4 is arranged in the center of the intake passage 2, and the fuel supplied from the fuel passage 5 is delivered to the throttle valve 3.
spray towards.

However, in such a conventional intake path device, most of the injected fuel adheres to the surface of the throttle valve 3 and the inner wall surface of the intake passage 2 and becomes liquid. Therefore, when the amount of intake air changes suddenly, such as when the engine accelerates or decelerates, the liquid fuel adhering to the inner wall of the intake passage 2 is instantly transferred to the throttle valve 3.
The exhaust gas composition (Co, HC) deteriorates as a rich mixture is generated and supplied. In addition, due to the inclination of the engine body and the inclination of the throttle valve 3, the liquid fuel flows unevenly to one side of the intake passage 2, resulting in uneven fuel distribution to each cylinder. There were problems such as smoldering of the spark plug due to the inflow of water and deterioration of fuel efficiency and exhaust composition.

This invention has been made in view of these conventional problems, and includes a cylindrical member that separates the intake passage from the inside and outside in the radial direction in the intake passage upstream of the throttle valve. By injecting fuel, fuel and air are continuously mixed in the center of the intake passage, preventing deterioration of the exhaust composition due to intermittent supply of fuel adhering to the intake passage wall, and increasing the amount of fuel to each cylinder. The aim is to prevent smoldering of spark plugs in specific cylinders and deterioration of fuel efficiency and exhaust composition by making the distribution uniform.

An intake passage device for an internal combustion engine according to the present invention includes an intake passage that introduces an air-fuel mixture into a combustion chamber of an engine, a throttle valve provided in the intake passage, and a throttle valve provided in the intake passage upstream of the throttle valve. a cylindrical member that separates the intake passage from the inside and outside;
The fuel injection valve includes a fuel injection valve that injects fuel toward the inner wall surface of the cylindrical member.

Embodiments of the present invention will be described below based on the drawings.

2 to 4 show an embodiment of this invention. In the figure, reference numeral 11 indicates an internal combustion engine, and reference numeral 12 indicates an intake passage that introduces an air-fuel mixture into a combustion chamber 13 of the internal combustion engine 11. That is, one end of the intake passage 12 is connected to the air cleaner 14.
The other end communicates with the combustion chamber 13 via the intake valve 15.
Connected.

A throttle valve 16 is disposed in the intake passage 12, and a substantially cylindrical cylindrical member 17 is disposed inside the intake passage 12 upstream of the throttle valve 16. This cylindrical member 17 separates the intake passage 12 inside and outside in its radial direction, and as shown in detail in FIGS. 3 and 4, the cross-sectional area of the intake passage 12 is It has a diameter of 1/3 or more (the diameter is also 1
/2 or more) The inner passage 18 is connected to the outside (the outer wall surface of the cylindrical member 17 and the throttle body that constitutes the intake passage I2).
An annular outer passage 19 is formed between the intake pipe body 21 and the inner wall surface of the intake pipe body 21. In addition, the inner wall surface 1 of the cylindrical member 17
Although the axial center portion of the cylindrical member 7a slightly protrudes inward, the ventilation resistance of the cylindrical member 17 as a whole is sufficiently small. Note that 22 in FIG. 3 indicates a bolt for fixing the cylindrical member 17 to the throttle body 21. Further, in the intake passage 12, a fuel injection valve 25 is disposed approximately at the center of the upstream side of the cylindrical member 17 (along the axis line) and is supported by support members 23 and 24. The injection valve 25 is a calculation device (microcomputer) that will be described later.
26 is electronically controlled by a built-in control circuit to inject fuel toward the inner passage 18, specifically toward the inner wall surface 17a of the cylindrical member 17. 27 and 28 are sealing members. Further, 29 is a fuel passage that supplies fuel from the fuel tank 31 to the fuel injection valve 25 . A hot water passage 32 is formed in the throttle body 21 on the side of the throttle valve 16, and engine cooling water flows into this passage 32 from an inlet 33 and flows out from an outlet 34. Also, in Figures 3 and 4, 3
5 is a negative pressure passage connected to an ignition advance device and the like.

Referring again to FIG. 2, a fuel pump 36, a filter 37, and a pressure regulator 38 are interposed in the fuel passage 29, and this pressure regulator 38 is located downstream of the throttle valve 6. It is controlled by a solenoid valve 41 interposed in a negative pressure passage 39 that takes out negative pressure. Note that the opening and closing of this solenoid valve 41 is controlled by the arithmetic unit 26.

Further, 42 is a fuel return passage. Furthermore, in the figure, 43 indicates an exhaust passage, and 44 indicates a catalytic converter with a built-in three-way catalyst, which is interposed in the exhaust passage 43.

The computing device 26 determines the operating state of the engine based on various input signals from the air flow meter 45, throttle switch 46, water temperature sensor 47, 02 sensor 48, rotation speed sensor 49, etc., and determines the optimum fuel*° for the state. It calculates and controls the I injection amount, that is, the valve opening pulse width of the fuel injection valve 25. Therefore, the fuel injection valve 25 opens every time the engine rotates based on the output signal of the control circuit of the arithmetic unit 26, and injects 1!1 of the engine-required fuel.

Next, the effect will be explained.

The arithmetic unit 26 determines the operating state of the engine 11 based on input signals from various sensors, and the control circuit outputs a signal with a pulse width optimal for the operating state to the fuel injection valve 25. As a result, the fuel injection valve 25 is driven to open each time the engine rotates,
Inject engine requested fuel. This injected fuel is annularly injected toward the inner wall surface 17a of the cylindrical member 17 as shown in FIG. do. At this time, the injected fuel adheres to the inner wall surface 17a of the cylindrical member 17 and becomes liquid, but the flow velocity of the intake air in the inner passage 18 located at the center of the intake passage 12 is high, and the fuel adhesion area (inner Wall surface 17
Since the area a) is smaller than that of the intake passage 12, vaporization of this liquid fuel is promoted. On the other hand, only the intake air taken in from the air conditioner 14 flows through the outer passage 9, and this intake air joins the rich air-fuel mixture in the intake passage 12 downstream of the cylindrical member 17 and mixes. air) to generate a mixture with a predetermined air-fuel ratio.

Thereafter, the air-fuel mixture is supplied to the combustion chamber 13 of the engine 11 via the throttle valve 16 and the intake manifold.

As a result, fuel does not adhere in liquid form to the inner wall surface of the intake passage 12 on the downstream side of the cylindrical member 17 due to the intake air flowing through the outer passage 19. It is possible to prevent the excessively rich mixture from suddenly flowing into the combustion chamber 13 and deteriorating the exhaust composition (Co, HC), and to uniformly distribute and supply the mixture with the same air-fuel ratio to each cylinder. Further, since the fuel injection valve 25 is disposed on the axis of the intake passage 12, the injected fuel is reliably injected toward the inner wall surface 17a (inner passage 1B) of the cylindrical member 17 and inside the throttle body 21 of the outer passage 19. Does not stick to walls. Further, the solenoid valve 41 is driven by an output signal from the arithmetic unit 26 to limit the intake pipe negative pressure acting on the pressure regulator 3B via the negative pressure passage 39 when the engine is at low temperature, at high load, and at engine overheat. By introducing atmospheric air, the set pressure of the pressure regulator 38 is increased, the fuel pressure is increased, and the amount of fuel can be easily increased. Furthermore, hot water from the engine 11 is introduced into the throttle body 21 on the side of the throttle valve 16. Since the hot water passage 32 is formed, the air-fuel mixture diluted and mixed on the downstream side of both the passages 18 and 19 is heated to further promote even mixing of the air-air mixture.

Note that when the inner wall surface 17a of the cylindrical member 17 is further protruded inward and formed into a venturi shape, the air flow velocity in the inner passage 18 is further increased, and it is possible to further prevent fuel from adhering to the inner wall surface 17a. Further, by arranging each bridge portion of the support member 23 and the cylindrical member 17 on the same plane that includes the axis of the intake passage 12, ventilation resistance can be reduced.

The bridge portion 23 has a rectifying effect, and the mixture generation in the cylindrical member 17 is stabilized. Further, by setting the number of fuel injections during idling to once for every two revolutions of the crank, it is possible to prevent variations in the amount of fuel injection.

As explained above, according to the present invention, it is possible to prevent the injected fuel from adhering in liquid form to the inner wall surface of the intake passage and the surface of the throttle valve, and it is possible to prevent the injected fuel from adhering in liquid form to the inner wall surface of the intake passage and the surface of the throttle valve. It is not supplied to the combustion chamber, and the exhaust composition (I
(C, C0), and also prevents liquid fuel from being supplied unevenly to each cylinder due to the inclination of the throttle valve or the inclination of the engine itself, improving starting performance, fuel efficiency, and driving performance. It can be improved and improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a conventional intake path device for an internal combustion engine, FIG. 2 is a schematic overall view showing an embodiment of the intake path device for an internal combustion engine according to the present invention, and FIG. FIG. 2 is a sectional view of a main part, and FIG. 4 is a view taken along the line rV-IV in FIG. 3. 12------One intake passage, 13---One combustion chamber, 16---One throttle valve, 17---One cylindrical member, 17 a---One cylindrical member inner wall surface, 18---
- one inner passage, 19 ---- outer passage, 25 ---- one fuel injection valve. Patent Applicant Nissan Motor Co., Ltd. Representative Patent Attorney Agagun Part 1 Figure 1

Claims (1)

[Claims] An intake passage that introduces an air-fuel mixture into an engine combustion chamber, a throttle valve provided in the intake passage, and a cylinder provided in the intake passage upstream of the throttle valve to separate the intake passage from inside and outside. An intake path device for an internal combustion engine, comprising: a cylindrical member; and a fuel injection valve that injects fuel toward an inner wall surface of the cylindrical member.