JPH059482Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mounting structure for an electric air control valve that controls the air-fuel mixture introduced into the intake manifold of an engine to be near the stoichiometric air-fuel ratio.

[Prior Art] As one of the prior art related to the present invention, Japanese Utility Model Application No. 60-81266 is known. In the engine air-fuel ratio control device disclosed in the present invention, auxiliary air is supplied to the engine intake system in addition to the air passing through the intake passage, and the auxiliary air is mixed by adjusting the flow rate of the auxiliary air with a solenoid valve. The air-fuel ratio of air is set at a target value. In this device, the solenoid valve is installed on the vehicle body,
Auxiliary air is taken in from the clean side of the air cleaner. The blow-by gas from the engine is introduced downstream of the air cleaner.

The above-mentioned solenoid valve has its opening degree changed in response to an electric signal from an electronic control device, and is usually called an electric air control valve (EACV). As mentioned above, the EACV is generally attached to the body side and connected to the intake manifold via a hose. Also, the EACV is sometimes attached to the engine, but in this case also it is connected to the intake manifold with a hose.

[Problems to be solved by the invention] In the engine equipped with the above-mentioned EACV, the O ₂ sensor installed on the exhaust manifold side is
F (air fuel ratio) is sensed and the result is judged by the CPU of the electronic control unit. This determined result is the EACV
EACV is driven based on this feedback. However, in a structure in which the EACV is connected to the intake manifold with a hose, the path becomes long, meaning that the EACV is located quite far from the O ₂ sensor, resulting in poor feedback control responsiveness. occurs.

Furthermore, since the EACV is a type of linear solenoid, it may not be able to maintain its normal function if it freezes in the middle of winter, so countermeasures are desired.

Furthermore, in conventional engines, fuel adhering to the inner wall of the intake manifold downstream of the carburetor flows along the inner wall, resulting in a rich air-fuel ratio in the #1 and #4 cylinders, which removes harmful substances contained in the exhaust gas. It was difficult to suppress the amount.

The present invention focuses on the above problems and improves the responsiveness of feedback control.
It can prevent the EACV from freezing, and it can also suppress fuel from adhering to the inner wall of the intake manifold, improving exhaust gas purification performance.
EACV (Electric Air Control Valve)
The purpose is to provide a mounting structure for.

[Means for solving the problem] The mounting structure of the electric air control valve according to the present invention that meets this purpose has a riser section that heats the part of the intake manifold located directly below the carburetor, and a riser section that heats the part of the intake manifold located directly below the carburetor, and a In an engine having an electric air control valve that increases or decreases the amount of air introduced into the intake manifold by changing the valve opening degree in response to a signal to control the air-fuel mixture to near the stoichiometric air-fuel ratio, the electric air control valve , directly installed on the intake manifold,
The air outlet of the electric air control valve is formed so that the air ejected from the air outlet is blown out toward the inner wall surface of the intake manifold.

[Function] In the electric air control valve installation structure configured as described above, the electric air control valve (EACV) is installed directly on the intake manifold, so the EACV is installed on the body side as in the conventional structure.
Moreover, the path is significantly shorter than in a configuration in which the EACV and the intake manifold are connected by a hose. Therefore, the feedback path of the entire system is shortened, and the responsiveness of feedback control is improved.

Furthermore, since the EACV is warmed by heat transfer from the intake manifold heated by the riser section, it is prevented from freezing even in the harshest of winters, and its functions are maintained normally.

Furthermore, since the air introduced into the intake manifold from the EACV is ejected from the air jet port toward the inner wall of the intake manifold, this airflow distributes the fuel adhering to the inner wall appropriately to each cylinder. Ru. Therefore, the air-fuel ratio of a specific cylinder is prevented from becoming richer, and the exhaust gas purification performance is improved.

[Embodiments] Hereinafter, preferred embodiments of the electric air control valve mounting structure according to the present invention will be described with reference to the drawings.

1 to 3 show an embodiment of the present invention. In the figure, 1 indicates a 4-cylinder gasoline engine. An intake manifold 2 of an engine 1 has a riser section 3 formed at its bottom that is heated by the temperature of cooling water flowing through a water jacket. Upstream of intake manifold 2,
A carburetor 5 is provided which atomizes the fuel, mixes it well with air, and provides a flammable air-fuel mixture to the combustion chamber 4. An air cleaner 6 is provided upstream of the carburetor 5 to supply clean air to the engine.

An electric air control valve (hereinafter referred to as "EACV") 7 is directly attached to a portion of the intake manifold 2 near the riser portion 3, which causes air from the clean side of the air cleaner 6 to flow into the intake manifold through a separate route.
The EACV 7 is connected to the clean side of the air cleaner 6 via a hose 8, and the air that has passed through the hose 8 is directed from the air outlet 9 of the EACV 7 to the lower inner wall surface 2a of the intake manifold 2, as shown in FIG. It's starting to squirt. That is, the fuel adhering to the inner wall surface 2a of the intake manifold 2 is evenly distributed from the #1 cylinder to the #4 cylinder by air from the EACV 7, as shown in FIG.

In this embodiment, the air outlet 9 is formed obliquely downward by an angle θ (for example, 5° to 30°) with respect to the horizontal axis A, and the air from the air outlet 9 is Air is ejected from an air supply port 13 that communicates with the outlet 9 and is provided at the very edge of the inner wall surface 2a of the intake manifold 2.

The EACV 7 is connected to an electronic control unit (ECU) 10 having a CPU. This EACV7
is configured to control the air-fuel mixture to near the stoichiometric air-fuel ratio by changing the valve opening according to an electrical signal from the electronic control device 10 and increasing or decreasing the amount of air introduced into the intake manifold 2.
An O ₂ sensor 12 is arranged in the exhaust manifold 11 to detect the oxygen concentration in exhaust gas. This O ₂ sensor 12 is connected to the electronic control device 10
The system is connected to the air-fuel ratio to detect the air-fuel ratio and provide feedback to the fuel system. That is, _O2
Based on the input signal from the sensor 12, the electronic control unit 10 outputs a signal to the EACV 7 to control the air-fuel ratio of the air-fuel mixture to near the stoichiometric air-fuel ratio.

Next, the operation of the above electric air control valve (EACV) mounting structure will be explained.

When the engine is started, air is introduced from the air cleaner 6, passes through the carburetor 5, and flows into the combustion chamber 4 together with the fuel spray generated by the carburetor 5. In this case, downstream of the carburetor 5, part of the atomized fuel adheres to the inner wall surface 2a of the intake manifold 2 and tries to flow along the inner wall surface 2a, but the air jet port 9 of the EACV 7
is formed so as to eject air toward the inner wall surface 2a to which the fuel is attached, so that the attached fuel is separated from the inner wall surface 2a by the air flow.
It is distributed almost evenly to each cylinder. Therefore, the air-fuel ratio of a specific cylinder is prevented from becoming rich.
Exhaust gas purification performance is improved.

FIG. 4 shows the relationship between the position of the air jet port 9 of the EACV 7 and the air-fuel ratio of each cylinder. B in the figure shows the characteristics of the present invention, and C in the figure shows the characteristics when the position of the air outlet is at the position of the two-dot chain line D shown in FIG. That is, by making the air ejected from the air ejection port 9 hit the lower inner wall surface 2a of the intake manifold 2, the variation in the air-fuel ratio of each cylinder can be suppressed to approximately 1%. As shown by the two-dot chain line in Fig. 2, with a structure in which air is simply injected into the center of the intake manifold 2, variations in the air-fuel ratio in each cylinder occur.
It increases to 1.5%. In other words, by applying air to the lower inner wall surface 2a where fuel tends to adhere,
The air-fuel ratio of the #2 cylinder and the #3 cylinder can be reduced, and it is possible to obtain a substantially uniform air-fuel ratio for each cylinder as a whole.

In addition, since the EACV 7 is directly attached to the intake manifold 2, it is possible to instantly blow out air into the intake manifold 2 when it receives an output signal from the electronic control device 10, which improves the responsiveness of feedback control compared to the conventional structure. is greatly improved.

Furthermore, the EACV7 is appropriately warmed by heat transfer from the riser section 3, which is heated by the temperature of the cooling water, so it will not freeze even in the harshest of winters.
Its function is maintained normally.

[Effects of the invention] As explained above, when using the electric air control valve mounting structure of the invention, the electric air control valve can be
Since it is directly attached to the intake manifold, the responsiveness of feedback control can be greatly improved compared to the conventional structure, and the electric air control valve can be reliably prevented from freezing during the harsh winter season.

In addition, the air outlet of the electric air control valve is formed so that air is injected toward the inner wall surface of the intake manifold.
It becomes possible to distribute fuel adhering to the inner wall surface almost uniformly to each cylinder, and it is possible to improve exhaust gas purification performance.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the mounting structure of an electric air control valve according to an embodiment of the present invention, and FIG. 2 is a sectional view of the vicinity of the air outlet of the electric air control valve in FIG. 1.
FIG. 3 is a sectional view of the vicinity of the intake manifold in FIG. 1, and FIG. 4 is a characteristic diagram showing the relationship between the position of the air jet port and the air-fuel ratio of each cylinder. 2... Intake manifold, 3... Riser section, 5... Carburetor, 7... Electric air control valve (EACV), 9... Air outlet, 10... Electronic control unit, 12... O ₂ sensor.

Claims (1)

[Scope of utility model registration request] The riser section heats the part of the intake manifold located directly below the carburetor, and the valve opening changes according to electrical signals from the electronic control device, which increases or decreases the amount of air introduced into the intake manifold, reducing the air-fuel mixture to stoichiometric air. In an engine having an electric air control valve that controls the fuel ratio near the fuel ratio, the electric air control valve is directly attached to the intake manifold, and the air jet port of the electric air control valve is connected to the air jet port to control the air jetted from the air jet port. A mounting structure for an electric air control valve, characterized in that the electric air control valve is formed so that air is ejected toward an inner wall surface of an intake manifold.