JPH02196121A - Supercharged internal combustion engine - Google Patents

Abstract

PURPOSE:To aim at the promotion of space-saving by assembling a relief valve, preventing supercharging pressure from going up so abnormally at deceleration, solidly in a secondary air control valve controlling an exhaust emission controlling secondary air quantity to be fed to an exhaust path, without entailing any damage to a control characteristic of the secondary air control valve. CONSTITUTION:An inlet chamber 16 being interconnected to the inside of a surge tank 11 via a passage 15 is installed in a valve box 14 in a secondary air control valve 13, while a first valve seat port 19 is installed in a part at the more downstream side than a valve body 18 set up between the inlet chamber 16 and an outlet chamber 17 and a second valve seat port 20 larger in diameter than the valve seat port 19 in a part at the more upstream side than the valve body 18, respectively. The outlet chamber 17 is interconnected to an exhaust manifold 4 via a secondary air supply passage 21. In addition, a relief chamber 29 is formed in the valve box 14, opening a relief passage 28 for being on standby. Then, the valve body 18 being connected to a diaphragm 25 via a valve stem 26 is installed in space between both these valve seat ports 19 and 20, while a relief valve body 31 for opening or closing a third valve seat port 30 is installed in this valve stem 26 free of sliding motion.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to supplying secondary air for exhaust gas purification to an exhaust path and preventing an abnormal increase in supercharging pressure to an intake path. This relates to a supercharged internal combustion engine that is compatible with

[Problems to be solved by conventional techniques and inventions] Generally,
To purify combustible harmful components in the exhaust gas of an internal combustion engine, secondary air is supplied upstream of a catalytic exhaust purification device installed in the exhaust system to oxidize the combustible harmful components in the exhaust gas. It is known that this is effective.

Therefore, Japanese Utility Model Application Publication No. 56-163712 as a prior art discloses that in a supercharged internal combustion engine, a secondary air supply passage is provided between the downstream side of the supercharger and the upstream side of the exhaust purification device. and by providing a secondary air control valve in this secondary air supply passage, which opens and closes in relation to the intake pressure at a location downstream of the throttle valve located downstream of the supercharger. , proposes to open the secondary air control valve to supply secondary air to the exhaust system in an operating range where the intake pressure is below atmospheric pressure.

In this case, the intake pressure downstream of the throttle valve decreases toward the vacuum side in proportion to the closing operation of the throttle valve, so that the secondary air control valve in the prior art opens in proportion to the closing operation of the throttle valve. Therefore, during idling operation with the throttle valve closed and deceleration with the throttle valve suddenly closed, the secondary air control valve opens wide and the amount of secondary air supplied to the exhaust system increases. .

However, during idling, when there are few flammable harmful components in the exhaust gas, the amount of secondary air supplied to the exhaust system increases because the temperature of the exhaust purification device decreases due to the supply of this large amount of secondary air. This leads to poor purification of the exhaust gas, and the fact that the amount of secondary air supplied to the exhaust system increases during deceleration, when the amount of combustible harmful components in the exhaust gas increases significantly, is due to this large amount of secondary air being supplied to the exhaust system. Since the temperature of the exhaust gas purification device becomes abnormally high due to the supply of air, the catalyst in the exhaust gas purification device deteriorates early.

On the other hand, in a supercharged internal combustion engine, the supercharged air from the supercharger is released into the atmosphere or an air cleaner during deceleration to prevent the supercharging pressure from becoming abnormally high during deceleration. However, in conventional supercharged internal combustion engines, this relief valve and the secondary air Since the control valve and the secondary air control valve are constructed separately, it is necessary to secure a space in the internal combustion engine to install the relief valve and the secondary air control valve. This resulted in an increase in weight and weight.

It is an object of the present invention to solve the problems of the prior art, and another object of the present invention is to change the control characteristics of the relief valve to the secondary air control valve. The goal is to integrate the system into one piece without damaging it.

[Means to solve the problem]

In order to achieve this object, the present invention provides a secondary air supply passage branched from a portion of the intake path between the supercharger and the throttle valve located downstream of the supercharger, and In a supercharged internal combustion engine which is connected to a side part and is provided with a pressure-operated secondary air control valve in the secondary air supply passage, the secondary air control valve has a valve box containing: A first valve seat port located on the downstream side of the valve body and a second valve seat port located on the upstream side of the valve body are arranged in series with respect to the flow direction of the secondary air. a spring configured to press the valve body against the first valve seat opening, and
This valve body is connected to a diaphragm that divides the valve body into a first pressure chamber and a second pressure chamber, and the pressure on the downstream side of the throttle valve is reduced to a negative pressure below atmospheric pressure in the first pressure chamber. Then, the valve body moves away from the first valve seat opening and moves to the second valve seat.
At the same time, the pressure between the supercharger and the throttle valve is introduced into the second pressure chamber so that when the pressure increases, the valve element moves away from the first valve seat opening. The valve box of the secondary air control valve further includes the first pressure chamber and the second pressure chamber.
A third valve seat opening is provided to discharge the supercharged air from the supercharger to the outside of the intake path when the pressure difference between the air pressure chamber and the pressure chamber is large.

[For production]

In this configuration, in idling operation with the throttle valve approximately fully closed, the pressure between the throttle valve and the supercharger is approximately atmospheric, while the pressure downstream of the throttle valve is below atmospheric pressure. , and a pressure difference is created between the first pressure chamber and the second pressure chamber in which the pressure in the first pressure chamber is lower than the pressure in the second pressure chamber, and the valve body Due to the large pressure difference, the second valve seat port is moved away from the first valve seat port against the spring applied to the valve body, and the second valve seat port is closed, thereby regulating the amount of secondary air supplied to the exhaust path to a small amount. Or, cut the secondary air supply to the exhaust path.

Next, in a partial load region with the throttle valve partially closed, the pressure downstream of the throttle valve increases to approach atmospheric pressure, resulting in a pressure difference between the first pressure chamber and the second pressure chamber. is smaller than that in the idling operation range, and the valve body is positioned at an intermediate position between the first valve seat port and the second valve seat port due to its spring, and the valve body is positioned between the first valve seat port and the second valve seat port. Since both of the two valve seat ports are open, secondary air is supplied to the exhaust path.

In a high load range where the opening of the throttle valve is large, the pressure between the turbocharger and the throttle valve increases due to the operation of the supercharger, and the pressure downstream of the throttle valve also increases. When the valve is opened, the pressure increases to be approximately equal to the pressure between the supercharger and the throttle valve, and there is almost no pressure difference between the first pressure chamber and the second pressure chamber. Body is,
The spring moves the valve away from the second valve seat and contacts the first valve seat, completely blocking the first valve seat, thereby preventing the supply of secondary air to the exhaust path. is cut.

Furthermore, when decelerating by suddenly closing the throttle valve, the pressure on the downstream side of the throttle valve becomes a large negative pressure below atmospheric pressure due to the sudden closing of the throttle valve, and the pressure in the first pressure chamber and the second pressure chamber is reduced. Due to this large pressure difference, the valve element moves away from the first valve seat opening against the spring applied to the valve element, as in the case of idling, and moves toward the second valve. Since it operates to close the seat, the amount of secondary air supplied to the exhaust path is regulated to a small amount, or the supply of secondary air to the exhaust path is cut. At the same time, the third valve seat opening opens and supercharged air from the supercharger is released outside the intake path, which prevents supercharging pressure from becoming abnormally high during deceleration of the internal combustion engine. .

〔Effect of the invention〕

Therefore, according to the present invention, when supplying secondary air for exhaust gas purification to the exhaust system of a supercharged internal combustion engine, the supply of secondary air during idling and deceleration is regulated to a small amount. Since the supply of secondary air during idling can reduce the purification of exhaust gas by the exhaust purification device, and the supply of secondary air during deceleration can reduce the purification of exhaust gas by the exhaust purification device. This can reliably prevent catalyst deterioration from accelerating.

Moreover, the present invention provides a valve box in a secondary air control valve that includes:
When the pressure difference between the first pressure chamber and the second pressure chamber is large,
By providing a third valve seat opening for discharging the supercharged air from the supercharger to the outside of the intake path, the secondary air control valve for controlling the secondary air can be used to reduce the deceleration of the internal combustion engine. A relief valve for releasing supercharged air at the time of the operation can be integrally incorporated without impairing the function of the secondary air control valve, that is, the control characteristics of the secondary air control valve. Therefore, it is possible to avoid an increase in the size and weight of the internal combustion engine when both a secondary air control valve and a relief valve are provided in the supercharged internal combustion engine.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 indicates an internal combustion engine, and reference numeral 2 indicates a roots type or movable airfoil type etc. which are rotationally driven by power transmission by a belt 3 from the internal combustion engine 1. A catalytic exhaust purification device 5 is connected to the exhaust manifold 4 from the exhaust boat 1a of the internal combustion engine 1, and a catalytic exhaust purification device 5 is connected to the intake side of the supercharger 2. is connected to an intake passage 7 from an air cleaner 6.

Further, reference numeral 8 indicates an intake bow) 1 in the internal combustion engine 1.
9 is a carburetor with a throttle valve 10 connected to the intake manifold 8, and 11 is a surtank connected to the carburetor 9. A supercharging passage 12 from the discharge side of the supercharger 2 is connected thereto.

Reference numeral 13 designates a pressure-operated secondary air control valve, and the secondary air control valve 13 includes an inlet chamber 16 in a valve box 14 that communicates with the surge tank 11 through a passage 15. , a first valve seat opening 19 with an inner diameter DI is disposed downstream of the valve body 18 disposed between the inlet chamber 16 and the outlet chamber 17, and a second valve seat opening 19 with an inner diameter D2 is disposed upstream of the valve body 18. A valve seat opening 20 is provided, and the outlet chamber 17 is communicated with the exhaust manifold 4 via a secondary air supply passage 21;
The valve body 18 between the first valve seat port 19 and the second valve seat port 20 is inserted into the diaphragm case 22 into the first pressure chamber 23.
and a second pressure chamber 24 via a valve shaft 26, and presses and urges the valve element 18 against the first valve seat opening 19 within the first pressure chamber 23. A spring 27 is provided for this purpose.

In this case, the diameter of the valve body 18 is the same as that of the first valve seat opening 1.
The inner diameter D2 of the second valve seat opening 20 is larger than the inner diameter D1 of the first valve seat opening 19 so as to completely block the valve body 18. It is configured to have a size slightly larger than the diameter of the valve body 18 so that it fits in with a small gap.

Further, a relief chamber 29 is formed in the valve box 14 of the secondary air control valve 13 and communicates with the air cleaner 6 or the relief passage 28 to the atmosphere, and the relief chamber 29 and the inlet chamber 16 are connected. A third valve seat opening 30 is formed, and a relief valve body 3 is provided in the relief chamber 29.
1 is provided so as to be slidably fitted onto the valve shaft 26,
The relief valve body 31 is pressed into contact with the third valve seat opening 30 by a spring 32 so as to close the third valve seat opening 30, while the valve body 18 is the second
A stopper 33 is provided so as to come into contact with the relief valve body 32 when the valve seat opening 20 is approached.

The first pressure chamber 2 in the secondary air control valve 13
3, a first pressure transmission passage 34 from the intake manifold 8 is connected to the second pressure chamber 24, and a second pressure transmission passage 36 from a pressure take-out boat 35 provided in the surge tank 11 is connected to the second pressure chamber 24.

In addition, a delay mechanism 39 is provided in the second pressure transmission passage 36, which includes a throttle orifice 37 and a check valve 38 that opens only in the direction toward the second pressure chamber 24, which are arranged side by side.
Further, an auxiliary pressure transmission passage 4o with a throttle orifice 41 of the intake manifold 8 is connected to the second pressure transmission passage 36, and furthermore, the surge tank 11 is provided with the pressure extraction port when the temperature is low. A temperature sensing valve 42 is provided which closes the pressure take-off boat 35 but opens the pressure take-off boat 35 when the temperature rises.

On the other hand, in the outlet chamber 17 of the secondary air control valve 13, a reed valve 43 is provided which opens only in the direction toward the exhaust manifold 4.

In this configuration, during cold operation at a low temperature, the temperature sensing valve 42 closes the pressure extraction port 35, so that the first pressure chamber 23 and the second pressure chamber 24 in the secondary air control valve 13 are closed. The pressure within the intake manifold 8 acts on both of them.

In this case, in an idling state with the throttle valve 10 substantially fully closed, the pressure within the intake manifold 8 becomes a negative pressure below atmospheric pressure, and this negative pressure is applied to the first pressure chamber 23 and the second pressure chamber 24. Since there is no pressure difference between the first pressure chamber 23 and the second pressure chamber 24, the valve body 18
As shown in FIG. 2, the spring 27
Although the first valve seat port 19 is closed while remaining in pressure contact with the exhaust manifold 5, secondary air is not supplied to the exhaust manifold 5.

Furthermore, even in a partial load region when the throttle valve 10 is partially closed, and in a high load region when the opening degree of the throttle valve 10 is increased, the first pressure chamber 23 and the second pressure chamber 2
4, the pressure within the intake manifold 8 acts simultaneously on both the first pressure chamber 23 and the second pressure chamber 2.
4, the valve body 18 remains in contact with the first valve seat port 19, and secondary air is not supplied to the exhaust manifold 5.

However, when decelerating by rapidly closing the throttle valve 10, the negative pressure in the intake manifold 8 is transmitted to the first pressure chamber 23 without any time delay, but the negative pressure in the intake manifold 8 is transmitted to the second pressure chamber 24. The negative pressure in the first pressure chamber 23 is transmitted between the first pressure chamber 23 and the second pressure chamber 24 with a time delay due to the delay mechanism 39. Due to the occurrence of a significantly large pressure difference that is lower than the pressure, the valve body 1
8 resists its spring 27 due to this extremely large pressure difference, and moves away from the first valve seat opening 19, as shown in FIG.
Since the exhaust manifold 4 operates so as to fit into the second valve seat opening 20, the second valve seat opening 20 and the valve body 1 are provided in the exhaust manifold 4.
A small amount of secondary air leaking from the gap with the valve 8 is supplied, and the relief valve body 31 is opened against the spring 32 by the stopper 33 provided on the valve shaft 26, and the third valve seat opening is opened. 30 is opened, excess air in the surge tank 11 is discharged to the air cleaner 6 or the atmosphere.

Then, after the delay time caused by the delay mechanism 39 has elapsed,
When the pressures in both pressure chambers 23, 24 become equal, the valve body 18 is moved by its spring 27, as shown in FIG.
At the same time that the first valve seat opening 19 is returned to the state of being closed, the relief valve body 31 is also returning to the state of closing the third valve seat opening 30.

Next, when the temperature has reached a predetermined temperature, the temperature sensing valve 42
However, by opening the pressure extraction boat 35, the pressure within the surge tank 11 is transmitted to the second pressure chamber 24 without any time delay due to the opening of the check valve 38 in the delay mechanism 39.

In this case, in an idling state with the throttle valve 10 substantially fully closed, the pressure in the surge tank 11 is substantially atmospheric, while the pressure in the intake manifold 8 downstream of the throttle valve 10 is atmospheric pressure. The following large negative pressure is created, and the first pressure chamber 23 and the second pressure chamber 24
There is a large pressure difference in that the pressure in the first pressure chamber 23 is lower than the pressure in the second pressure chamber 24, and this large pressure difference causes the valve body 18 to Against the spring 27, as shown in FIG.
Since it operates to close the second valve seat port 20 away from the first valve seat port 19, the amount of secondary air supplied to the exhaust manifold 4 is regulated to a small amount.

In a partial load region when the throttle valve 10 is partially loaded, the pressure in the intake manifold 8 downstream of the throttle valve increases to approach atmospheric pressure, and the pressure between the first pressure chamber 23 and the second pressure chamber 24 increases. As the pressure difference becomes smaller, the valve element 18 is positioned at an intermediate position between the first valve seat opening 19 and the second valve seat opening 20 due to its spring, as shown in FIG. Since both the first valve seat port 19 and the second valve seat port 20 are open, secondary air is supplied to the exhaust manifold 4.

In a high load range where the opening degree of the throttle valve 10 is large,
Due to the operation of the supercharger 2, the pressure in the surge tank 11 increases, and the pressure in the intake manifold 8 also increases to be approximately equal to the pressure in the surge tank 11 due to the opening of the throttle valve 10, and the pressure in the first pressure chamber increases. 2
3 and the second pressure chamber 24, the valve body 18 is moved away from the second valve seat opening 20 by its spring 27, as shown in FIG. 1
The first valve seat port 19 operates so as to come into contact with the valve seat port 19.
Since the exhaust manifold 4 is completely blocked, the supply of secondary air to the exhaust manifold 4 is cut off.

In addition, when decelerating by rapidly closing the throttle valve 10,
The pressure in the intake manifold 8 downstream of the throttle valve becomes a large negative pressure below atmospheric pressure due to the sudden closing of the throttle valve 10, and the first pressure chamber 23 and the second pressure chamber 24
As the pressure difference between
Due to this significantly large pressure difference, the valve body 18 resists the spring 27 against the valve body 18, as shown in FIG.
Since the valve moves away from the first valve seat opening 19 and fits into the second valve seat opening 20, the amount of secondary air supplied to the exhaust manifold 4 is reduced between the second valve seat opening 20 and the valve body. 18, and the relief valve body 31 is opened against the spring 32 by the stopper 33 provided on the valve shaft 26, and the third valve seat port 30 is opened. Excess air in the surge tank 11 is released to the air cleaner 6 or the atmosphere.

On the other hand, the pressure in the surge tank 11 is constantly acting on the relief valve body 31, and while the internal combustion engine is in operation, the pressure in the surge tank 11 is increased due to deceleration in the internal combustion engine, high rotation, etc. When the pressure exceeds a predetermined setting value, the relief valve body 31 operates to open the third valve seat port 30 against the spring 32 against the relief valve body 31 due to this pressure. A part of the supercharged air from the charger 2 is released from the third valve seat port 30 to the air cleaner 6 or the atmosphere.

In other words, the relief valve body 31 and the third
The valve seat port 30 performs two functions: to release supercharging air during deceleration, and as a relief valve to regulate and control the supercharging pressure so that it does not exceed a predetermined value. .

In addition, in the above embodiment, the supply amount of secondary air during idling and deceleration is determined based on the inner diameter D2 of the second valve seat opening 20 and the valve body 18.
Although we have shown a case in which the amount of secondary air is regulated to a small amount by making the diameter larger than the diameter of It goes without saying that the structure may be constructed so as to generate a complete force of 70%, and that it can also be used in an exhaust turbocharged internal combustion engine.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is an overall view, FIG. 2 is an enlarged longitudinal sectional front view of the secondary air control valve, and FIGS. 3, 4, and 5 are views of the secondary air control valve. It is a figure which shows an operating state. 1...Internal combustion engine, 2...Supercharger, 4...Exhaust manifold, 5...Exhaust purification device, 6...
Air cleaner, 8... Intake manifold > 9...
・Carburizer, 10... Throttle valve, 11... Surge tank, 13... Secondary air control valve, 14...
・Valve box, 16...Entrance chamber, 17...Outlet chamber, 1
8... Valve body, 19... First valve seat opening, 20...
・Second valve seat port, 21...Secondary air supply passage, 22 23...First pressure chamber, 2...Diaphragm, 26 28...Relief passage, 0... 3rd valve seat opening, 31 2... Spring. ... diaphragm case, 4 ... second pressure chamber, 25 ... valve stem, 27 ... spring, 29 ... relief chamber, 3 ... valve body for relief, 3

Claims (1)

[Claims] (1) Connect the secondary air supply passage branching from the part of the intake path between the turbocharger and the throttle valve located downstream thereof to the part of the exhaust path upstream of the exhaust purification device. In a supercharged internal combustion engine that is provided with a pressure-operated secondary air control valve in the secondary air supply passage, the valve body of the secondary air control valve includes a valve on the downstream side of the valve body. A first valve seat port located on the upstream side of the valve body and a second valve seat port located on the upstream side of the valve body are arranged in series with respect to the flow direction of the secondary air, a spring configured to press the valve body against the first valve seat opening, the valve body being connected to a diaphragm that partitions the valve body into a first pressure chamber and a second pressure chamber, and the throttle valve being connected to the first pressure chamber. The pressure on the downstream side of the valve is introduced so that when the pressure becomes a negative pressure below atmospheric pressure, the valve element moves away from the first valve seat opening and moves toward the second valve opening, while the second pressure Introducing pressure between the supercharger and the throttle valve into the chamber such that when the pressure increases, the valve body moves away from the first valve seat port and toward the second valve seat port, and further, In the valve box of the secondary air control valve, there is a valve that discharges supercharged air from the supercharger to the outside of the intake path when the pressure difference between the first pressure chamber and the second pressure chamber is large. A supercharged internal combustion engine characterized by having three valve seats.