JPS645077Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is an internal combustion engine equipped with a supercharger such as an exhaust turbo supercharger in the intake system. The present invention relates to a device for controlling the opening and closing of a secondary throttle valve of a type carburetor.

[Conventional technology]

The throttle valve on the secondary side of a dual carburetor used in a normal internal combustion engine without a supercharger is
It is configured to open using a negative pressure diaphragm mechanism that utilizes the fact that the negative pressure in the primary ventilate increases toward the vacuum side as intake air increases.
When a dual carburetor is installed downstream of the supercharger in a supercharged internal combustion engine, negative pressure will not be generated in the primary ventilate due to supercharging pressure.
The secondary throttle valve cannot be opened or closed using the pressure in the primary ventilate.

Therefore, Japanese Utility Model Application Publication No. 57-134351 as a prior art discloses that in a supercharged internal combustion engine, a secondary throttle valve in a dual carburetor installed on the downstream side of a supercharger is used to vaporize via a diaphragm mechanism. It is related to the pressure upstream of the vaporizer, and it is proposed to open in response to the pressure rising from a certain value upstream of the vaporizer.

[Problem that the invention attempts to solve]

However, in a dual carburetor in which the secondary throttle valve is operated by a diaphragm mechanism, the secondary throttle valve cannot be opened due to digging into the valve bore or contact resistance when the secondary throttle valve is closed. In order to prevent this from happening, there is a gap between the primary throttle valve and the secondary throttle valve that opens the secondary throttle valve to a small opening (approx. A pickup mechanism is provided to forcibly open the throttle valve (3 degrees), but when the secondary throttle valve begins to open, supercharging by the supercharger has progressed to a certain extent, and the pressure upstream of the carburetor increases. The boost pressure is higher than atmospheric pressure, and in the prior art, this boost pressure acts on the pressure chamber in the diaphragm mechanism of the secondary throttle valve when the secondary throttle valve begins to open. Therefore, when the kick-up mechanism for the secondary throttle valve operates at this time, the secondary throttle valve opens rapidly and due to the operation of the kick-up mechanism and the supercharging pressure acting on the pressure chamber. It will open more than once.

Therefore, due to the sudden opening of the secondary throttle valve, a large amount of air flows, and the intake air mixture to the engine becomes extremely lean, causing a so-called secondary shock in which the output of the mechanism temporarily decreases. , the acceleration feeling was poor.

The purpose of this invention is to accurately prevent the occurrence of secondary shock when a dual carburetor is applied to a supercharged internal combustion engine without impairing the responsiveness of the opening operation of the secondary throttle valve. That is.

[Means for solving problems]

For this reason, the present invention provides a dual carburetor downstream of the supercharger with a kick-up mechanism that opens the secondary throttle valve by a small amount when the primary throttle valve is almost fully opened. In the internal combustion engine with a supercharger, the secondary side throttle valve of the dual carburetor is provided with a diaphragm mechanism configured to open the secondary side throttle valve in response to a rise in pressure in the pressure chamber, and the A pressure extraction port is provided on the secondary side of the carburetor at a position that is downstream when the secondary throttle valve is closed and upstream when the secondary throttle valve is open. and the pressure chamber of the diaphragm mechanism are connected through a pressure transmission passage, and a restriction orifice is provided in the pressure transmission passage.

[Functions and effects of the idea]

With this configuration, the pressure transmitted from the pressure extraction port provided on the secondary side to the pressure chamber in the diaphragm mechanism of the secondary throttle valve is
When the secondary throttle valve is closed, the boost pressure on the upstream side of the carburetor is smaller than the flow resistance caused by the primary ventilate, and after the secondary throttle valve opens and operates by the kick-up mechanism, vaporization occurs. The boost pressure increases to the upstream side of the device, and the increase in pressure in this pressure chamber is delayed by the throttle orifice installed in the pressure transmission passage, so the secondary throttle valve When the valve is initially opened by the mechanism, it does not open wide due to supercharging pressure.

In this case, when the configuration is such that the pressure on the downstream side of the carburetor is applied to the pressure chamber in the diaphragm mechanism for the secondary throttle valve, that is, the pressure extraction port is always located downstream of the secondary throttle valve. When located at
The pressure acting on the pressure chamber in the diaphragm mechanism increases after the secondary throttle valve is opened by the kick-up mechanism. Although it is possible to prevent it from opening wide at the beginning, the pressure downstream of the carburetor is
It is lower than the boost pressure on the upstream side of the carburetor by the resistance of the primary throttle valve and the secondary throttle valve, so when the secondary throttle valve opens and operates following the increase in boost pressure. This will result in a decrease in responsiveness.

In contrast, the present invention provides a pressure outlet port for the diaphragm mechanism at a position that is downstream when the secondary throttle valve is closed and upstream when the secondary throttle valve is open. When the secondary throttle valve is opened by the kick-up mechanism, this pressure extraction port is located upstream of the secondary throttle valve and is located at approximately the supercharging pressure (supercharging on the upstream side of the carburetor). (lower than the pressure by the resistance of the secondary ventilate) acts on the pressure chamber in the diaphragm mechanism, so the response when the secondary throttle valve opens and operates in response to the increase in boost pressure decreases. This can be prevented.

Therefore, according to the present invention, it is possible to reliably prevent the occurrence of secondary shock without causing a decrease in response when the secondary throttle valve opens and operates, so that the acceleration feeling in a supercharged internal combustion engine can be accurately controlled. It has the effect of improving

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 indicates an internal combustion engine equipped with an intake manifold 2 and an exhaust manifold 3, and reference numeral 4 indicates an exhaust turbo in which an exhaust turbine 5 and a blower 6 are directly connected. Each supercharger is shown, and in the intake passage 7 that connects the discharge side of the blower compressor 6 in the exhaust turbo supercharger 4 and the intake manifold 2, there is a surge tank 8 for eliminating pulsation and a dual carburetor 9. Toga,
A surge tank 8 is provided upstream of the carburetor 9, an air cleaner 10 is connected to the suction side of the blower compressor 6, and an air cleaner 10 is connected to the inlet side of the exhaust turbine 5 via an exhaust passage 11. An exhaust pipe 12 to the atmosphere is connected to the exhaust manifold 3 and to the outlet side of the exhaust turbine 5, respectively.

On the primary side 13 of the dual carburetor 9,
A primary throttle valve 14 that opens when an accelerator pedal (not shown) is depressed is provided, and a secondary throttle valve 16 is provided on the secondary side 15, so that the primary throttle valve 14 and the secondary throttle valve A valve is connected to the valve 16 so that when the primary throttle valve 14 opens nearly fully open, the secondary throttle valve 16 is forcibly opened by a small angle (approximately 3 degrees) from the fully closed position. A conventionally known pickup mechanism (not shown) is provided.

Reference numeral 17 denotes a diaphragm mechanism for the secondary throttle valve 16, and the diaphragm mechanism 1
7 is provided with a spring 18 and a pressure chamber 19 that urge the secondary throttle valve 16 to be normally closed.

On the other hand, on the secondary side 15 of the vaporizer 9,
A pressure extraction port 20 is provided at a position that is downstream when the secondary throttle valve 16 is closed and upstream when the secondary throttle valve 16 is open, and the pressure extraction port 20 and the diaphragm mechanism 17 The pressure chamber 19 is connected to the pressure chamber 19 through a pressure transmission passage 21, and a restriction orifice 22 is provided in the pressure transmission passage 21.

In this configuration, in an operating range where the primary throttle valve 14 of the carburetor 9 is slightly opened, the amount of exhaust gas from the engine is small, the rotational speed of the exhaust turbocharger 4 is low, and the pressure on the upstream side of the carburetor 9 is low. does not rise significantly, while the secondary throttle valve 16 remains closed and the pressure at the port 20 on the secondary side 15 increases by the flow resistance of the intake air as it passes through the ventilator section on the primary side 13. This pressure acts on the pressure chamber 19 in the diaphragm mechanism 17.

When the opening degree of the primary throttle valve 14 is increased, the pressure on the upstream side of the carburetor 9 gradually increases and becomes a supercharging pressure higher than atmospheric pressure. A pressure lower than the supercharging pressure by the amount of flow resistance in the ventilate section of the primary side 13 acts, and the primary side throttle valve 14 is almost fully opened and the kick-up mechanism is operated, thereby increasing the secondary side throttle valve 16. When the pressure extraction port 20 is opened, the pressure extraction port 20 becomes upstream of the secondary side throttle valve 16, and the pressure at the 20 pressure extraction ports is approximately the supercharging pressure (lower than the supercharging pressure at the ventilator on the secondary side 15). (lower value due to the flow resistance of the
Pressure chamber 1 in diaphragm mechanism 17 via
9. In other words, the pressure in the pressure chamber 19 in the diaphragm mechanism 17 is
The pressure is lower than the pressure on the upstream side of the carburetor 9 until the throttle valve 6 opens, and after the secondary throttle valve 16 starts to open, the pressure rises to approach the pressure on the upstream side of the carburetor, and the pressure in the pressure chamber 19 of the diaphragm mechanism increases. Since the pressure rise in is delayed by the throttle orifice 22 in the pressure transmission passage 21, the supercharging pressure upstream of the carburetor 9 is added to the opening operation of the secondary throttle valve 16 at the time of opening. The secondary throttle valve 16 will not open more than the opening of the pickup mechanism.

Further, the secondary throttle valve 16 opens following the boost pressure on the upstream side of the secondary throttle valve 16, so the secondary throttle valve opens following the increase in boost pressure. This can prevent the responsiveness during operation from decreasing.

Although the above embodiment was applied to an internal combustion engine equipped with an exhaust turbo supercharger, the present invention is not limited to this, and can be applied to a machine in which a blower compressor is rotationally driven by an internal combustion engine. Needless to say, the same applies to internal combustion engines equipped with a supercharger.

[Brief explanation of drawings]

The drawings are diagrams showing embodiments of the present invention. 1...Internal combustion engine, 2...Exhaust manifold, 4
...Exhaust turbo supercharger, 7...Intake passage, 9...
Dual carburetor, 13...Primary side, 15...Secondary side, 14...Primary side throttle valve, 16...Secondary side throttle valve, 17...Diaphragm mechanism, 1
9...Pressure chamber, 20...Pressure extraction port, 21
...Pressure transmission passage, 22... Throttle orifice.

Claims (1)

[Scope of utility model registration request] An internal combustion engine equipped with a supercharger, which is equipped with a double carburetor downstream of the supercharger, which has a kick-up mechanism that opens the secondary throttle valve by a small amount when the primary throttle valve is almost fully opened. In the engine, a secondary throttle valve of the dual carburetor,
A diaphragm mechanism is provided on the secondary side of the carburetor to open the secondary throttle valve in response to a rise in pressure in the pressure chamber. A pressure extraction port is provided at a position that is upstream of the next throttle valve when it is opened, and the pressure extraction port and the pressure chamber in the diaphragm mechanism are connected via a pressure transmission passage, and the pressure transmission A control device for a secondary throttle valve in a dual carburetor for an internal combustion engine with a supercharger, which has a throttle orifice in its passage.