JPS5920851B2 - Internal combustion engine with supercharger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a supercharged engine and controls the operation of the supercharger according to the operating state of the engine.

There are various types of turbochargers, such as mechanical and exhaust pressure types, but conventional turbocharged engines provide turbocharging from the throttle valve half-open operating range to the fully open operating range, and exhaust bypass is used for boost pressure that exceeds the required level. Alternatively, it is attempted to improve the output when the engine is fully opened by taking measures such as intake bypass.

However, it is not advisable to perform supercharging over the entire operating range of the engine.

This is because, for example, in the case of exhaust pressure supercharging, the pressurized intake air is throttled by the throttle valve when the engine is operated, so there is no point in supercharging (not only that, but supercharging is The exhaust gas is passed through the turbine of the supercharger, and at that time, the exhaust pressure is not increased, which reduces the intake efficiency of intake air to the engine, reduces the amount of intake air, and thus causes a decrease in output.

In addition, supercharging over the entire operating range requires the turbocharger body,
This has the disadvantage that a load is always applied to the exhaust system and the intake system, which is disadvantageous in terms of durability.

Therefore, the present invention aims to provide a supercharged engine that eliminates the above-mentioned drawbacks by operating the supercharger only in the full-throttle operation range, including sudden acceleration, and keeping the supercharging pressure at that time below the set pressure. With the goal.

The present invention will be explained in detail below with reference to embodiments shown in the drawings.

In FIGS. 1 and 2 showing the first embodiment, 1 is an engine body, 2 is an intake system attached to the engine body 1, and this intake system 2 is connected to an air cleaner 3. It is composed of an intake air amount detector 4, intake pipes 5 and 6, and an intake manifold 7. A throttle valve 8 is provided in the intake pipe 6, and the throttle valve 8 is operated in conjunction with an accelerator pedal 9. Opens and closes the inside of the intake pipe 6.

10 is an exhaust system attached to the engine body 1, and this exhaust system 10 includes an exhaust manifold 11, an exhaust pipe 12 communicating with this exhaust manifold 11, and a bypass exhaust pipe 13 connected in parallel with this exhaust pipe 12. , an exhaust relief pipe 14 connecting the exhaust pipe 12 and the bypass exhaust pipe 13.

Reference numeral 17 denotes a known exhaust pressure type supercharger, and this supercharger 17 has a built-in turbine that is rotated by the fluid energy of the exhaust gas flowing through the exhaust pipe 12. It communicates with the intake pipe 5, the intake and discharge ports communicate with the intake pipe 6, and the exhaust gas intake and discharge ports communicate with the exhaust pipe 12.

18 is a first valve body that selectively opens and closes the exhaust passage 12a in the exhaust pipe 12 and the bypass exhaust passage 13a in the bypass exhaust pipe 13; 19 is a first driving means for driving the valve body 18; The valve body 18 has a valve stem 191 attached to one end, a diaphragm 192 connected to the other end of the valve stem 191, and two chambers 193 separated by the diaphragm 192.
194 and installed in the first chamber 193 and the exhaust passage 12
The spring 195 urges the valve body 18 in the direction of opening the valve a.

Note that the first chamber 193 communicates with the intake manifold 1 via pressure passages 28 and 29, and the second chamber 194 is open to the atmosphere.

Reference numeral 30 denotes a second valve body that closes the exhaust gas passage 14a in the exhaust gas relief pipe 14, and 31 denotes a second driving means for driving the second valve body 30, to which the valve body 30 is attached at one end. A valve stem 311, a diaphragm 312 connected to the other end of the valve stem 31.1, two chambers 313 and 314 separated by the diaphragm 312, and an exhaust relief passage 14a installed in the first chamber 313. The spring 315 urges the valve body 30 in the closing direction.

Note that the first chamber 313 is open to the atmosphere, and the second chamber 313 is open to the atmosphere.
4 communicates with the intake manifold 7 via pressure passages 39 and 29.

Further, the exhaust pipe 12 includes a first valve body 18 that connects the exhaust passage 12.
A bypass passage 12b is provided that allows part of the exhaust gas to pass through to the exhaust passage 12a side when the exhaust gas is fully opened.

41 indicates a fuel system, which includes a fuel tank 42 and a fuel filter 4.
3, a fuel pump 44, a fuel regulator 45, a fuel conduit 46, a fuel injection valve 47, a computer 48, and a lead wire 49.

The operation of the above configuration will be explained.

When the engine 1 is operated, the amount of intake air is determined according to the open state of the throttle valve 3, the amount of intake air is measured by the intake air amount detector 4, and the amount of fuel commensurate with the amount of intake air is determined by the computer 48. Then, fuel is injected into the engine 1 from the fuel injection valve 41.

Fuel is always pumped from the fuel tank 42 through the fuel filter 43 by the fuel pump 44, and then pumped up by the regulator 45.
The pressure is controlled to be constant by the fuel injection valve 47 via the fuel conduit 46.

In the half-open operating range of the throttle valve 80, the intake air is throttled by the throttle valve 8, and negative pressure is generated within the intake manifold 7.

The negative pressure enters the first chamber 193 of the first driving means 19 through the pressure passages 29 and 28, and the first valve body 18 is moved to the left as shown in FIG. and closes the exhaust passage 12a.

Further, the negative pressure enters the second chamber 314 of the second driving means 31 through the pressure passages 29, 39, and the second valve body 30 is moved as shown in FIG. As shown (moved to the left to close the exhaust relief passage 14a).

Therefore, the exhaust gas discharged from the engine 1 is discharged to the atmosphere via the bypass exhaust passage 13a.

At this time, part of the exhaust gas flows into the exhaust passage 12a via the bypass passage 12b, thereby causing the turbine of the supercharger 17 to rotate at a low rotation speed, preventing seizure of the turbine shaft and delaying response during sudden acceleration. Make smaller.

Note that the return force of the spring 195 and the pressure receiving area of the diaphragm 192 are set so that this state is maintained when the intake pressure downstream of the throttle valve 8 is, for example, less than 80 mvtHg.

Furthermore, when the intake pressure reaches -80 mrnHg, the first valve element 18 gradually begins to open the exhaust passage 12a, and as the pressure increases further, the first valve element 18 moves in the direction of closing the bypass exhaust passage 13a, and the intake air For example, the pressure is -20mrrt
The bypass exhaust passage 13a is set to be fully closed by Hg.

Therefore, when the boost pressure is low in the full-throttle operation range including sudden acceleration (e.g. -20 mmHg or more and less than +180 muHg)
A small negative pressure or positive pressure acts on the first chamber 193 of the first driving means 19, and the first valve body 18 fully opens the bypass exhaust passage 13a.

On the other hand, the above pressure also acts on the second chamber 314 of the second driving means 31, but at less than +180 mrrtHg, the return force of the spring 315 is overwhelming, and the second valve element 30 keeps the exhaust relief passage 14a closed. do.

Therefore, all the exhaust gas discharged from engine 1 is transferred to exhaust passage 1.
2a and is used to rotate the turbine of the supercharger 17.

Since the turbine and blower of the supercharger 17 rotate by the same shaft, the blower pressurizes the intake air to the engine 1 by effectively utilizing exhaust energy.

The pressurized intake air enters the engine 1 and contributes to an increase in output.

When the boost pressure is high in the full-open operation region (e.g. +180
mmHg or more), the first valve body 18 opens the exhaust passage 12a, while the second drive means 31 opens the second chamber 31.
When the intake pressure applied to 4 increases (for example, +18
0 mmHg or more), the second valve body 30 opens the exhaust gas relief passage 14a against the return force of the spring 315, allowing a portion of the exhaust gas to escape from the exhaust passage 12a to the bypass exhaust passage 13a. This reduces the exhaust energy applied to the turbine of the supercharger 17.

That is, the supercharging effect by the blower becomes small, and the supercharging pressure supplied to the engine 1 becomes small.

Moreover, if it becomes too low, the second valve body 30 will be removed from the relief passage 14.
a, and ultimately maintains a constant boost pressure.

Therefore, the supercharging pressure will not be higher than necessary.

The above-mentioned set intake pressure is just an example, and the point is to vary the operation depending on the operating state of the engine 1.

Next, a second embodiment shown in FIG. 3 will be described.

This is a modification of the first driving means 19, which includes a shaft 501 that rotates in conjunction with the throttle valve 8, and a shaft 501 that rotates in conjunction with the throttle valve 8.
A first driving means 50 is constituted by a rotating piece 502 that rotates together with the rotating piece 502, a valve stem 503 that transmits the movement of the rotating piece 502 to the first valve body 18, and a return spring 504.
move the valve body 18.

To explain the operation, when the throttle valve 8 is in a half-open state (for example, less than 415 degrees of opening), the first valve body 18 is in the state shown in FIG. 3, and most of the exhaust gas flows into the bypass exhaust passage 13a, and some Exhaust passage 12a via bypass passage 12b
flows to

When the throttle valve 8 is fully open (for example, 415 degrees or more open), the shaft 501 and the rotating piece 502 rotate clockwise against the return force of the return spring 504, and the first valve body 18 opens the exhaust passage 12a. Open.

Therefore, all the exhaust gas flows through the exhaust passage 12a, and the supercharger 11 pressurizes the intake air to increase the output.

When the intake pressure exceeds, for example, +180 mmHg, the second valve body 30 opens the exhaust relief passage 14a to keep the supercharging pressure constant, as in the previous embodiment.

Therefore, the same operation and effect as in the first embodiment can be obtained.

In the above-described embodiment, the first driving means 19 and 50 are those that utilize the intake pressure of the engine 1 or those that operate in conjunction with the throttle valve 8, but the point is that the first driving means 19 and 50 are those that utilize the intake pressure of the engine 1 or those that are linked to the throttle valve 8. Any structure may be used as long as it can detect whether it is in the operating region or not.

As described above, the present invention closes the exhaust passage when the engine is in the half-open operating region and opens the bypass exhaust passage to prevent exhaust gas from acting on the turbocharger turbine. This avoids an increase in exhaust pressure, and therefore, there is no decrease in the intake efficiency of intake air to the engine (therefore, there is no decrease in the amount of intake air, so it is possible to prevent a decrease in output due to the installation of a supercharger in the half-open operating range).

Furthermore, by bypassing the exhaust gas, the durability of the intake system or exhaust system of the supercharger body can be improved.

Furthermore, when the boost pressure is low in a full-throttle operation region including sudden acceleration, the bypass exhaust pipe is closed and all exhaust gas flows to the turbocharger side, increasing the efficiency (operating the turbocharger to increase the boost pressure). can be increased.

Furthermore, when the supercharging pressure becomes higher than the set pressure in the full-throttle operation region, the exhaust relief passage is opened and the intake pressure is controlled to the set pressure, which prevents engine knocking due to high supercharging. It has the excellent effect of preventing damage to the main body, engine body, exhaust system, or intake system.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing a first embodiment of the present invention, FIG. 2 is a sectional view of a main part thereof, and FIG. 3 is a sectional view of a main part of a second embodiment of the invention. 1... Internal combustion engine, 8... Throttle valve, 12... Exhaust pipe, 13... Bypass exhaust pipe, 14... Exhaust relief Tube, 17...
・Supercharger, 18...First valve body, 19.50・
...First driving means, 30... Second valve body, 31... Second driving means.

Claims (1)

[Claims] 1. In a supercharged internal combustion engine equipped with a supercharger that is driven by exhaust gas flowing through an exhaust pipe and supplies supercharged air to the internal combustion engine, from the exhaust pipe between the internal combustion engine and the supercharger. A branched bypass exhaust pipe and an exhaust relief pipe, a first valve body that opens and closes the exhaust pipe and the bypass exhaust pipe, and a first valve body that drives the first valve body according to the operating state of the internal combustion engine. a second valve body that opens and closes the exhaust relief pipe; and a second valve body that operates according to the intake pressure downstream of the throttle valve that adjusts the intake air amount of the internal combustion engine.
A supercharged internal combustion engine, comprising a second driving means for driving a valve body.