JPH06146909A - Output improvement device of supercharged engine - Google Patents

Abstract

PURPOSE:To maintain a supercharging effect by actuating exhaust gas in high pressure to an exhaust turbine before the gas in a cylinder is exchanged, and to facilitate flow-in of air-fuel mixture to a cylinder and discharge of exhaust gas from the cylinder by decreasing exhaust gas pressure at the time of exchanging the gas in the cylinder so as to improve engine output. CONSTITUTION:One side exhaust valve 1 is closed at the time of opening of an intake valve 3, and the other exhaust valve 2 not communicated with an exhaust turbine is opened at the same time and thereby the air is discharged in a supercharged engine where two exhaust valve 1, 2 and one intake valve 3 are provided, an exhaust turbine 6 is rotated by the exhaust gas 8 discharged from the side exhaust valve 1, and air-fuel mixture 9 is compressed by a compressor 7 on the same axial line as the exhaust turbine 6, and air is sucked by the intake valve 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power boosting device for a supercharged engine.

[0002]

2. Description of the Related Art An exhaust gas turbine, a gasoline engine, a diesel engine, etc. exhaust gas energy is used to rotate an exhaust turbine, and a coaxial compressor is provided.
An engine equipped with a supercharger, which is a device that compresses intake air by driving the engine and supplies high-density intake air above atmospheric pressure to the engine, is called a supercharged engine. Supercharging is particularly advantageous for diesel engines and contributes to engine output improvement. All large engines used in modern cogeneration are supercharged engines.

[0003]

However, in a supercharged engine, when the load is high, the exhaust pressure on the exhaust turbine side becomes high, and when the gas of the engine is exchanged, that is, when the intake valve and the exhaust valve are open at the same time, the gas is not generated. It becomes difficult for the fuel-air mixture to enter the cylinder, which increases the amount of residual exhaust gas in the cylinder and prevents the output of the engine from increasing.

FIG. 3 is a graph showing the opening / closing timings of the exhaust valve and the intake valve in the supercharged engine. The vertical axis shows the exhaust valve and the intake valve, and the horizontal axis shows the valve opening / closing time. The black circles in the graph indicate the opening time, and the white circles indicate the closing time.

As can be seen from FIG. 3, in the case of the conventional example, the exhaust valve opens at t _{1 and} closes at t ₃ . Also,
The intake valve opens at t _{2 and} closes at t ₃ . t ₂
Between t ₃ is the time of the gas exchange of the cylinder. At this time,
As described above, there is a drawback in that a mixture of gas and fuel, that is, intake air is difficult to enter the cylinder.

The present invention has been made in view of the above points. In a supercharged engine, before the cylinder gas is exchanged, high pressure exhaust gas is applied to the exhaust turbine to maintain the supercharge effect, and the cylinder gas exchange is performed. (EN) Provided is an output improving device capable of lowering exhaust pressure at a time, facilitating inflow of air-fuel mixture into a cylinder and discharging exhaust gas from a cylinder, reducing residual amount of exhaust gas, and thereby improving engine output. That is the purpose.

[0007]

In order to solve the above-mentioned problems, the present invention provides a cylinder with two exhaust valves and one intake valve, and an exhaust turbine is rotated by exhaust gas discharged from one exhaust valve. In the supercharging engine in which the air-fuel mixture is compressed by the compressor coaxial with the exhaust turbine and is sucked from the intake valve, the one exhaust valve is closed when the intake valve is opened, and at the same time, the other exhaust valve that is not in communication with the exhaust turbine is closed. It is characterized in that the exhaust valve is opened to exhaust air.

[0008]

[Operation] Since high-pressure exhaust gas acts on the exhaust turbine until the exhaust valve communicating with the exhaust turbine is closed, a supercharging effect is generated, and the exhaust valve communicating with the exhaust turbine is closed when the air-fuel mixture is inhaled. Moreover, when the exhaust valve that is not in communication with the exhaust turbine is opened, the exhaust pressure decreases, so that the exhaust gas is easily discharged from the cylinder and the air-fuel mixture easily flows into the cylinder. Therefore, the residual exhaust gas in the cylinder is scavenged and the air-fuel mixture is filled.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing a schematic configuration of an output improving apparatus for a supercharged engine according to the present invention. In FIG. 1, an exhaust valve 1, an exhaust valve 2, and an intake valve 3 are attached to a cylinder 4 of a supercharged engine.
And the spark plug 5 is arranged. An exhaust turbine 6 is arranged in an exhaust pipe communicating with the exhaust valve 1, a compressor 7 is arranged in an intake pipe communicating with the intake valve 3, and the exhaust turbine 6 and the compressor 7 are coaxially fixed. It constitutes a supercharger.

The air-fuel mixture is ignited in the cylinder 4 by the spark plug 5 and burned, and the exhaust gas flows from the exhaust valve 1 to the arrow B.
When discharged in the direction, the exhaust turbine 6 is rotated by the energy of the exhaust gas, and as a result, the compressor 7 fixed coaxially with the exhaust turbine 6 is driven.

The air-fuel mixture flowing in the direction of arrow A through the intake pipe is compressed by the rotation of the compressor 7, becomes a high density above atmospheric pressure, and flows into the cylinder 4 through the intake valve 3. In this way, the supercharger including the exhaust turbine 6 and the compressor 7 performs supercharging.

According to the invention, the exhaust gas is also discharged from the other exhaust valve 2. The exhaust gas emitted from the exhaust valve 2 is not used for the supercharger.

Next, the operation of the output improving apparatus for the supercharged engine of the present invention having the above construction will be described.

FIG. 2 is a diagram showing opening / closing of an exhaust valve and an intake valve used in the output improving apparatus for a supercharged engine of the present invention.
(A) shows the operation of the exhaust valve used for the supercharger, (b)
Indicates the operation of the exhaust valve not used for the supercharger.

FIG. 3 is a graph showing the opening / closing timings of the exhaust valve and the intake valve. The vertical axis shows the exhaust valve 1, the exhaust valve 2 and the intake valve 3 of the present invention, and the horizontal axis shows the valve opening / closing time. The black circles in the graph indicate the opening time, and the white circles indicate the closing time.

At t ₁ , the exhaust valve 1 opens and enters the exhaust stroke, the piston rises, and the exhaust gas 8 is exhausted through the exhaust valve 1. This state is shown in FIG. In this state, the pressure of the exhaust gas 8 in the exhaust pipe connected to the exhaust valve 1 is high,
The exhaust turbine 6 is rotating.

At t ₂ , the exhaust valve 1 is closed and the exhaust valve 2 and the intake valve 3 are opened. The exhaust gas 8 in the cylinder is discharged from the exhaust valve 2, the air-fuel mixture 9 flows from the intake valve 3 into the cylinder 4, and the gas exchange timing of the cylinder 4 is entered. This state is shown in Fig. 2 (b).
Shown in. In this state, the pressure in the exhaust pipe connected to the exhaust valve 2 is low, so that the exhaust gas 8 easily flows out through the exhaust valve 2 and the air-fuel mixture 9 easily flows in, so almost all the exhaust gas 8 is mixed with the air-fuel mixture 9. Be scavenged by.

At t ₃ , the exhaust valve 2 is closed, gas discharge from the cylinder is stopped, the gas exchange time is over, and the cylinder 4 is filled with the air-fuel mixture 9.

At t ₄ , the intake valve 3 closes.

[0021]

As described above, according to the present invention, 2
One exhaust valve and one intake valve are provided, and the supercharger is operated by the exhaust gas discharged from one exhaust valve,
This exhaust valve is closed when the intake valve is opened, and the other exhaust valve is opened to exhaust the exhaust gas, so the exhaust gas is sufficiently scavenged from the cylinder by the air-fuel mixture, and the amount of residual exhaust gas in the cylinder decreases. The excellent effect that the ratio of the air-fuel mixture is increased and the engine output is improved is obtained.

[Brief description of drawings]

FIG. 1 is a plan view showing a schematic configuration of an output improving device for a supercharged engine of the present invention.

FIG. 2 is a diagram showing opening and closing of an exhaust valve and an intake valve used in a supercharged engine output improving apparatus of the present invention, (a) showing an operation of an exhaust valve used in a supercharger, and (b). Indicates the operation of the exhaust valve not used for the supercharger.

FIG. 3 is a graph showing opening / closing timings of an exhaust valve and an intake valve in a supercharged engine.

[Explanation of symbols]

 1, 2 Exhaust valve 3 Intake valve 4 Cylinder 5 Spark plug 6 Turbine 7 Compressor 8 Exhaust gas 9 Mixture

Claims (1)

[Claims] 1. Two exhaust valves and one intake valve are provided, and exhaust gas discharged from one exhaust valve rotates an exhaust turbine to compress an air-fuel mixture by a compressor coaxial with the exhaust turbine. In a supercharged engine that intakes air from an intake valve, the one exhaust valve is closed when the intake valve is opened, and at the same time, the other exhaust valve that is not in communication with the exhaust turbine is opened and exhausted. Supercharged engine output improvement device.