JP2021124093A - Suction system for engine - Google Patents

Abstract

To provide a suction system for an engine capable of suppressing the lowering of volume efficiency and improving the homogeneity of gas fuel.SOLUTION: Between a gas injector 31 and a branch part 13 of a suction port 10, an umbrella shaped valve 40 is provided having a conical umbrella part 42 and a shaft part 43 where a wheel 44 moves for changing an opening angle of the umbrella part 42. The shaft part 43 extends along an injection direction of the gas injector 31. The umbrella part 42 is arranged at a position and in an attitude such as to collide with gas fuel injected from the gas injector 31 to diffuse the gas fuel and such that the vertical projection area of the umbrella part 42 to a plane vertical to the axial direction of the shaft part 43 is larger as an opening angle α of the umbrella part 42 is larger.SELECTED DRAWING: Figure 2

Description

The present invention relates to an engine intake system.

As an intake device for a conventional engine, the one described in Patent Document 1 is known. Patent Document 1 provides an airflow control valve for adjusting the opening area of the intake passage in the intake manifold on the upstream side of the injection portion (gas fuel injection position) of the gas injection valve in the intake manifold. Further, Patent Document 1 describes that closing the airflow control valve promotes mixing of gas fuel and air in the intake passage to generate a homogeneous air-fuel mixture.

Japanese Unexamined Patent Publication No. 2013-231428

However, in the intake device of the engine described in Patent Document 1, the air flow control valve arranged on the upstream side of the gas injection valve narrows the intake passage and causes pressure loss, so that the volumetric efficiency is lowered. There is a problem that the decrease in volumetric efficiency causes a decrease in engine output, especially during high-load operation of the engine.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an engine intake device capable of suppressing a decrease in volumetric efficiency and improving the homogeneity of gas fuel. Is to be.

The present invention bifurcates between an upstream portion consisting of one flow path opening on the surface of the cylinder head, a downstream portion consisting of two flow paths communicating with the combustion chamber, and the upstream portion and the downstream portion. An intake device for an engine including an intake port having a branch portion, a gas injector arranged in the upstream portion and injecting gas fuel toward the branch portion, and the gas injector and the branch portion. An umbrella-shaped valve having a conical umbrella-shaped portion and a shaft portion that changes the opening angle of the umbrella-shaped portion is provided between them, and the shaft portion extends along the injection direction of the gas injector. The umbrella-shaped portion collides with the gas fuel injected from the gas injector to diffuse the gas fuel, and the larger the opening angle of the umbrella-shaped portion, the more perpendicular to the axial direction of the shaft portion of the umbrella-shaped portion. It is characterized in that it is arranged in a position and orientation in which the vertical projection area on a plane becomes large.

As described above, according to the present invention, it is possible to provide an engine intake device capable of suppressing a decrease in volumetric efficiency and improving the homogeneity of gas fuel.

1 (A), 1 (B), and 1 (C) are plan views of an intake passage of an engine including an intake device for the engine according to an embodiment of the present invention. FIG. 2 is a plan view of an umbrella-shaped valve of an intake device of an engine according to an embodiment of the present invention. FIG. 3 is a block diagram of a control device for an intake device of an engine according to an embodiment of the present invention. FIG. 4 is a flowchart showing a control operation of the control device of the intake device of the engine according to the embodiment of the present invention. FIG. 5 is a control map that the control device of the intake device of the engine according to the embodiment of the present invention refers to during the control operation.

The intake device of the engine according to the embodiment of the present invention includes an upstream portion consisting of one flow path opening on the surface of the cylinder head, a downstream portion consisting of two flow paths communicating with the combustion chamber, and an upstream portion. An intake device for an engine including an intake port having a bifurcated branch portion between downstream portions and a gas injector arranged in the upstream portion and injecting gas fuel toward the branch portion. An umbrella-shaped valve having a conical umbrella-shaped portion and a shaft portion that changes the opening angle of the umbrella-shaped portion is provided between the and the branch portion, and the shaft portion is provided along the injection direction of the gas injector. The umbrella-shaped portion extends and collides with the gas fuel injected from the gas injector to diffuse the gas fuel, and the larger the opening angle of the umbrella-shaped portion, the more the flat surface perpendicular to the axial direction of the shaft portion of the umbrella-shaped portion. It is characterized in that it is arranged at a position and a posture in which the vertical projection area of is large. Thereby, the intake device of the engine according to the embodiment of the present invention can suppress the decrease in volumetric efficiency and can improve the homogeneity of the gas fuel.

Hereinafter, the intake device of the engine according to the embodiment of the present invention will be described with reference to the drawings. 1 to 5 are views showing an intake device of an engine according to an embodiment of the present invention. In FIGS. 1 to 5, the up-down, front-back, left-right directions are the up-down, front-back, left-right directions of the engine installed in the vehicle, the direction orthogonal to the front-back direction is the left-right direction, and the height direction of the engine is the up-down direction. ..

First, the configuration will be described. In FIGS. 1 (A), 1 (B), and 1 (C), the engine 1 includes a cylinder head 2. The cylinder head 2 is provided with a combustion chamber 7 for burning a mixture of fuel and air, and an intake port 10 for introducing the mixture into the combustion chamber 7. Further, the cylinder head 2 is provided with an exhaust port (not shown), and the exhaust port takes in the exhaust gas after combustion of the air-fuel mixture from the combustion chamber 7 and discharges it to the outside of the cylinder head 2.

The intake port 10 is between an upstream portion 11 composed of one flow path opening on the surface of the cylinder head 2, a downstream portion 12 composed of two flow paths communicating with the combustion chamber 7, and an upstream portion 11 and a downstream portion 12. It has a bifurcated portion 13 and a bifurcated portion 13.

Liquid fuel injectors 30 are provided in the two downstream portions 12 of the intake port 10, and the liquid fuel injector 30 injects liquid fuel (gasoline in this embodiment) into the downstream portions 12.

A gas injector 31 is provided in the upstream portion 11 of the intake port 10, and the gas injector 31 injects gas fuel toward the branch portion 13.

An umbrella-shaped valve 40 is provided between the gas injector 31 and the branch portion 13.

In FIG. 2, the umbrella-shaped valve 40 has a conical umbrella-shaped portion 42, a potter's wheel 44 that changes the opening angle of the umbrella-shaped portion 42, and a shaft portion 43 to which the potter's wheel 44 moves. The shaft portion 43 extends along the injection direction of the gas injector 31.

Further, it has a rib 41 provided in the umbrella-shaped portion 42 so as to maintain the shape of the umbrella-shaped portion 42, and a receiving bone 45 connecting the joint 46 of the rib-shaped portion 41 and the potter's wheel 44. The plurality of ribs 41 are connected to one end of the shaft portion 43. As described above, the umbrella-shaped valve 40 is configured in the same manner as an umbrella such as an umbrella.

In the umbrella-shaped valve 40, when the potter's wheel 44 moves on the shaft portion 43, the receiving bone 45 connected to the potter's wheel 44 changes the angle of the rib 41, and the opening angle α of the umbrella-shaped portion 42 changes.

The umbrella-shaped portion 42 is arranged at a position and a posture in which the gas fuel collides with the gas fuel injected from the gas injector 31 to diffuse the gas fuel. Further, the umbrella-shaped portion 42 is arranged at a position and a posture in which the larger the opening angle α of the umbrella-shaped portion 42, the larger the vertical projection area of the umbrella-shaped portion 42 on the plane perpendicular to the axial direction. .. Here, the vertically projected area of the umbrella-shaped portion 42 is, in other words, the area of the umbrella-shaped portion 42 when viewed along the axial direction of the shaft portion 43.

In this embodiment, in the intake port 10, the umbrella-shaped portion 42 has a shape on one side of the downstream portion 12 so that the intake amount is equal to each of the downstream portions 12 bifurcated at the branch portion 13. The shapes on the other side are formed to be equal. Specifically, the umbrella-shaped portion 42 is formed plane-symmetrically with respect to a plane passing through the shaft portion 43 and parallel to the axial direction of the shaft portion 43.

In the umbrella-shaped valve 40 of this embodiment, the axial dimension of the shaft portion 43 when the opening angle α of the umbrella-shaped portion 42 is reduced can be made smaller than the dimension of the conventional rotary valve. Therefore, the degree of approach of the umbrella-shaped valve 40 to the gas injector 31 can be reduced. As a result, the influence of the umbrella-shaped valve 40 on the flow of intake air can be suppressed.

In this embodiment, the umbrella-shaped valve 40 is arranged near the upstream side of the wall of the branch portion 13. The vicinity of the upstream side of the branch portion 13 of the intake port 10 is a portion at the downstream end of the upstream portion 11, and an umbrella-shaped valve 40 is provided at this portion. Therefore, the formation of the flow vortex can be minimized, and the decrease in volumetric efficiency can be suppressed. In addition, the umbrella-shaped valve 40 can be easily attached.

In FIG. 3, the engine 1 includes a control device 50 and an actuator 54. The actuator 54 operates so as to change the position of the upper wheel 44 of the shaft portion 43. A signal from the airflow sensor 51 that measures the intake air amount, an injector pulse signal 52, and an engine rotation speed 53 are input to the control device 50. The control device 50 operates the actuator 54 based on these signals to adjust the opening angle α of the umbrella-shaped portion 42 of the umbrella-shaped valve 40.

The control device 50 includes a CPU, RAM, ROM, etc. (not shown), and the CPU executes a program stored in the ROM by using the RAM to perform a control operation.

Next, the control operation by the control device 50 will be described. In FIG. 4, the control device 50 determines the degree of load of the engine 1 based on the input signal (step S1).

Next, the control device 50 determines the opening angle α of the umbrella-shaped portion 42 based on the degree of load and the engine speed with reference to the control map of FIG. 5 (step S2). In the control map of FIG. 5, it is defined that the opening angle α is increased in the region where both the engine speed and the load are small, and the opening angle α is decreased in the region where both the engine speed and the load are large.

Next, the control device 50 determines the position of the potter's wheel 44 according to the opening angle α (step S3), and drives the actuator 54 so as to reach the determined position of the potter's wheel 44 (step S4).

The control device 50 repeatedly executes steps S1 to S5 to control the opening angle α of the umbrella-shaped portion 42 of the umbrella-shaped valve 40 according to the load of the engine 1 and the engine speed. The control device 50 controls so that the opening angle α becomes large when the load of the engine 1 is small (when the load is low) (see FIG. 1C), and when the load of the engine 1 is large (when the load is high). ) Is controlled so that the opening angle α becomes small (see FIG. 1 (A)). Further, when the load of the engine 1 is larger than that at the time of low load and smaller than that at the time of high load, the control device 50 has an opening angle α between the opening angle α at the time of low load and the opening angle α at the time of high load. (See FIG. 1 (B)).

As described above, in the intake device of the engine 1, a conical umbrella-shaped portion 42 and a potter's wheel 44 that changes the opening angle α of the umbrella-shaped portion 42 move between the gas injector 31 and the branch portion 13. An umbrella-shaped valve 40 having a shaft portion 43 and the shaft portion 43 is provided. The shaft portion 43 extends along the injection direction of the gas injector 31. Further, the umbrella-shaped portion 42 collides with the gas fuel injected from the gas injector 31 to diffuse the gas fuel, and the larger the opening angle α of the umbrella-shaped portion 42, the more the shaft of the shaft portion 43 of the umbrella-shaped portion 42. It is arranged at a position and orientation in which the vertical projection area on a plane perpendicular to the direction is large.

With this configuration, the decrease in volumetric efficiency can be suppressed by reducing the opening angle α of the umbrella-shaped portion 42. Further, by increasing the opening angle α of the umbrella-shaped portion 42, the gas fuel collides with the umbrella-shaped portion 42 and diffuses, so that the homogeneity of the gas fuel can be improved.

As a result, it is possible to provide an engine intake device capable of suppressing a decrease in volumetric efficiency and improving the homogeneity of the gas fuel.

Further, the intake device of the engine 1 has a control device 50 that controls the opening angle α of the umbrella-shaped portion 42, and the control device 50 opens the umbrella-shaped portion 42 in the high load region of the engine 1 rather than in the low load region. The angle α is controlled to be small.

With this configuration, in the high load region of the engine, the decrease in volumetric efficiency can be suppressed by reducing the opening angle α of the umbrella-shaped portion 42.

Further, in the low load region of the engine, the homogeneity of the gas fuel can be improved by increasing the opening angle α of the umbrella-shaped portion 42.

Although the embodiments of the present invention have been disclosed, it is clear that some skilled in the art can make changes without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

1 ... engine, 2 ... cylinder head, 7 ... combustion chamber, 10 ... intake port, 11 ... upstream part, 12 ... downstream part, 13 ... branch part, 31. .. Gas injector, 40 ... Umbrella-shaped valve, 42 ... Umbrella-shaped part, 43 ... Shaft part, 50 ... Control device

Claims (2)

An upstream portion consisting of one flow path that opens on the surface of the cylinder head, a downstream portion consisting of two flow paths communicating with the combustion chamber, and a bifurcated branch portion between the upstream portion and the downstream portion. With an intake port,
An intake device for an engine including a gas injector arranged in the upstream portion and injecting gas fuel toward the branch portion.
An umbrella-shaped valve having a conical umbrella-shaped portion and a shaft portion that changes the opening angle of the umbrella-shaped portion is provided between the gas injector and the branch portion.
The shaft portion extends along the injection direction of the gas injector and extends.
The umbrella-shaped portion collides with the gas fuel injected from the gas injector to diffuse the gas fuel, and the larger the opening angle of the umbrella-shaped portion is, the more perpendicular to the axial direction of the shaft portion of the umbrella-shaped portion. An engine intake device characterized in that it is arranged in a position and orientation in which the vertical projection area on a flat surface becomes large. It has a control device that controls the opening angle of the umbrella-shaped portion, and has
The intake device for an engine according to claim 1, wherein the control device is controlled so that the opening angle of the umbrella-shaped portion is smaller in the high load region of the engine than in the low load region.

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