JPH06323144A - Intake pipe for spark ignition internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce a fuel consumption amount by providing a pipe for branching an air flow just after the downstream of a butterfly valve, and opening the other end of the branch pipe to an inlet part of a cylinder of an intake pipe so as to give a turning motion to the air flow. CONSTITUTION:A throttle valve 8 is provided in the upstream part of an intake pipe 4 through a distribution part 7 and opened/closed to be associated with an accelerator pedal. An inlet nozzle of a branch flow path 9 is opened just after the downstream of a throttle valve 8. The downstream end of the branch flow path is obliquely connected to a cylinder just before part of the intake pipe. When a valve plate 11 of the throttle valve 8 is placed in an intermediate opening, a negative pressure is generated to a cylinder inlet in the downstream of the valve due to intake action. Consequently, a flow is generated in the branch flow path 9 by a difference between inlet/outlet pressures, to blow out to the intake pipe in a cylinder inlet part. This jet flow, having an angle relating to an intake pipe wall surface normal, holds angular momentum to generate a turning flow after flowing in a cylinder. Thus, a fuel consumption amount can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake pipe for supplying air to a spark ignition internal combustion engine, and more particularly to a highly efficient intake pipe for an automobile internal combustion engine which reduces fuel consumption.

[0002]

2. Description of the Related Art A vehicle engine is a vehicle
The output changes depending on the acceleration. In normal constant speed driving, the engine is generally operated at a power much lower than the maximum power output. Therefore, in order to improve the fuel consumption, that is, reduce the fuel consumption, the reduction of the fuel consumption at the partial load is an important issue. Therefore, in a gasoline engine, an operating method for reducing the ratio of fuel to air, that is, the fuel-air ratio at the time of partial load, below the theoretical fuel-air ratio has been studied and is about to be adopted. However, if the amount of fuel is reduced, there arises a problem that combustion of a mixed gas of fuel and air becomes unstable at the time of ignition, or ignition becomes difficult. Therefore, the conventional gasoline engine sometimes employs the intake pipe as shown in FIG.

In this gasoline engine, the intake pipe 4 is divided into two parts, and a valve 12 is provided on one side. Valve 12 at maximum output
Is fully opened and operates as if there were no valve. During partial load, the valve 12 is closed and air is supplied only from the intake pipe 4 on one side where no valve is provided. Therefore, the air flowing into the cylinder 2 has an angular momentum, and a swirling flow is generated in the cylinder 2. As a result, the mixing of air and fuel is improved and, at the same time, combustion is improved due to the turbulence generated by the flow.

On the other hand, such a structure also causes the following problems. One is that the number of movable parts such as valves that are opened and closed according to the output increases, and the other is that the valve plate is present in the intake pipe, which increases the flow resistance of air, although it is fully opened. The maximum output of the engine is reduced.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a swirling motion component to the air flowing into a cylinder at the time of partial load without adding any movable part and without providing a member in the intake pipe. is there.

[0006]

In order to solve the above problems, in the present invention, a flow path branched immediately downstream of the throttle valve is connected to the intake pipe immediately before the cylinder. The branch portion immediately after the throttle valve is provided at a position on the upstream side of the valve plate when the throttle valve is wide open, and on the downstream side of the valve plate when the throttle valve opening is small (during idling). At the connection point immediately in front of the cylinder, the branch flow passage is opened so as to flow in at an angle to the normal to the wall surface of the intake pipe.

[0007]

The throttle valve is opened and closed according to the output required of the engine. At high output, the throttle valve is fully opened, so that no flow occurs in the branch flow passage and no flow resistance is generated. When the output is low, the inlet of the branch flow passage is located upstream of the valve plate of the throttle valve, so flow occurs in the branch flow passage, and at the cylinder inlet of the intake pipe, there is an angle with respect to the flow in the intake pipe central axis direction. Air with momentum flows in. This angular momentum does not disappear even after entering the cylinder, and causes a swirling flow in the cylinder.

[0008]

Embodiments of the present invention will be described with reference to FIGS. 1, 3, and 4 to 6. An exhaust pipe 3 and an intake pipe 4 are provided above a cylinder 2 having a piston 1 inside. Cylinder 2
And the exhaust pipe 5 and the intake pipe 4, respectively, at the boundary of the exhaust valve 5,
An intake valve 6 is provided and opens and closes in conjunction with a crankshaft connected to the piston 1. A throttle valve 8 is provided upstream of the intake pipe 4 via the distributor 7, and opens and closes in conjunction with the accelerator pedal. Although not shown, there are a plurality of cylinders (4 cylinders in this case).
Cylinder) and branches from the distributor 7 to form one throttle valve 8
Connected to. The branch passage 9 is provided immediately after the throttle valve 8 on the downstream side.
The entrance nozzle is open. The downstream end of the branch flow passage is obliquely connected to the intake pipe immediately before the cylinder, as shown in FIG. The branch channel 9 is branched at the branch section 10 on the way,
It is connected to the entrance of each cylinder.

Next, the operation will be described. FIG. 4 shows a state of the throttle valve 8 at the time of constant speed traveling in which the effect of the present invention is required. The valve plate 11 of the throttle valve has an intermediate opening, and a negative pressure is exerted up to the inlet of the cylinder on the downstream side of the valve due to the intake operation. Therefore, a flow is generated in the branch flow passage 9 due to the pressure difference between the inlet and the outlet, and blows out to the intake pipe at the cylinder inlet. Since this jet has an angle with respect to the normal to the wall surface of the intake pipe, it retains angular momentum, and instead of flowing uniformly in the intake pipe, a swirl flow is generated after flowing into the cylinder. In the case of this figure, since the flow velocity on the lower side of the intake pipe (lower side of this figure) is high, a counterclockwise (in this figure) swirling flow occurs in the cylinder.

FIG. 5 shows a state in which the engine is required to fully output and the throttle valve 8 is fully opened. At this time, no large pressure loss occurs before and after the throttle valve 8, and almost no flow occurs in the branch flow passage 9. Therefore, the maximum output does not decrease due to the influence of the present invention.

Throttle valve 8 when the engine is idling
The state is shown in FIG. The throttle valve 8 is almost closed, and air is passed to maintain the rotation of the engine. At this time as well, no flow occurs in the branch flow passage 9, and even though the throttle valve 8 is closed, air does not flow into the cylinder and the output of the engine does not decrease.

Another embodiment of the present invention is shown in FIG. The difference from that shown in FIG. 3 is that the intake pipe 4 has two intake valves.
Is that it is divided into two. The branch flow passage 8 is open to the intake pipe on one side. The operation is similar to that described above.

The direction of the angular momentum differs depending on the method of connecting the outlet of the branch flow passage to the intake pipe. The connection method can be selected depending on the direction of the swirling flow desired to be generated in the cylinder. In order to increase the swirl flow, the absolute value of the outer product V × N of the momentum vector V of the fluid at the outlet of the branch passage 8 and the vector N representing the perpendicular line drawn from the outlet to the central axis of the intake pipe is made as large as possible. The branch passage outlet mounting angle may be selected so that

[0014]

According to the present invention, there is no need to add a movable part and no member is provided in the intake pipe flow path.
A swirl force can be applied to the intake air at partial load.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a plan view of a conventional example.

FIG. 3 is a plan view of a connection structure of a branch flow path outlet.

FIG. 4 is a cross-sectional view of a state of a throttle valve portion during traveling at a constant speed.

FIG. 5 is a cross-sectional view of a state of the throttle valve portion at full output.

FIG. 6 is a cross-sectional view of a state of a throttle valve portion when idling.

FIG. 7 is a plan view of another embodiment of the present invention.

[Explanation of symbols]

 2 ... Cylinder, 4 ... Intake pipe, 8 ... Throttle valve, 9 ... Branch flow passage.

Claims (1)

[Claims] 1. A spark ignition internal combustion engine in which an output is controlled by a butterfly valve provided in an intake pipe, a pipe for branching an air flow is provided immediately downstream of the butterfly valve, and a branch portion is provided in accordance with an opening of the butterfly valve. Is located on the upstream side of the valve plate and on the downstream side of the valve plate, and the other end of the pipe is opened at the inlet of the cylinder of the intake pipe so as to give a swirling motion to the air flow. The intake pipe of a spark ignition internal combustion engine.