JPH022451B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine equipped with a supercharger.

Conventionally, in engines equipped with a supercharger, in order to avoid supercharging, a bypass passage that bypasses the turbine part of the supercharger is connected to the exhaust passage, and this bypass passage is connected to the exhaust passage. A waste gate valve is installed to open and close the

This wastegate valve is often driven by a pressure-responsive actuator, but when changing the boost pressure control characteristics in such a type, the pressure acting on the actuator is released to the atmosphere through a leak passage. Measures such as leaking information are being taken.

However, with such conventional means, when sludge due to blow-by gas etc. adheres to the leak passage and the passage area changes, it becomes impossible to accurately control the opening timing of the waste gate valve.
There is a risk that the boost pressure will rise abnormally.

The present invention aims to solve these problems, and the actuator has a double diaphragm structure with two diaphragms so that at least two types of boost pressure characteristics can be obtained, and these boost pressure characteristics can be used selectively. An object of the present invention is to provide a supercharged engine capable of avoiding an abnormal increase in supercharging pressure.

For this reason, the supercharged engine of the present invention includes a supercharger consisting of a turbine disposed in an exhaust passage and a compressor disposed in an intake passage and driven by the turbine. In the engine, the engine includes a bypass passage connected to the exhaust passage to bypass the exhaust passage, a waste gate valve that opens and closes the bypass passage, and a pressure-responsive actuator that opens and closes the waste gate valve. A first diaphragm connected to the waste gate valve via a first rod, a second diaphragm connected to a second rod that can be moved into and out of the first diaphragm, and a second diaphragm connected to the waste gate valve in the closing direction. a first return spring that biases;
a second return spring biasing the second rod away from the first diaphragm; and a second return spring formed between the first diaphragm and the second diaphragm and separated from the atmosphere via the first diaphragm. and a second pressure chamber formed adjacent to the first pressure chamber via the second diaphragm, and the first pressure chamber is provided with atmospheric pressure or pressure in the intake passage. A first control passage with a switching valve that can selectively introduce compressor downstream pressure is connected to the second pressure chamber, and a second control passage that can introduce compressor downstream pressure in the intake passage is connected to the second pressure chamber. , when compressor downstream pressure is acting on the first pressure chamber due to the action of the switching valve, when the pressure in the first pressure chamber exceeds the first set positive pressure, the first diaphragm switches to the first pressure chamber. When the waste gate valve is operated to open against the biasing force of the return spring, and atmospheric pressure is acting on the first pressure chamber due to the action of the switching valve, the pressure in the second pressure chamber is When the second set positive pressure is exceeded, the second diaphragm
The present invention is characterized in that it is configured to operate to open the waste gate valve via the second rod and the first diaphragm against the biasing force of a return spring and the biasing force of the second return spring.

Hereinafter, a supercharged engine as an embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is an overall configuration diagram thereof, Figs. 2 and 3 are graphs for explaining its operation, and Fig. 5 is a schematic diagram showing a modification of the actuator, and FIGS. 6 and 7 are graphs for explaining the action of the actuator shown in FIGS. 4 and 5, respectively.

As shown in FIG. 1, this engine is equipped with a supercharger (turbocharger) 3, which includes a turbine 4 installed in the exhaust passage 2 of the engine, and a turbine 4 installed in the intake passage 1 of the engine. The compressor 5 is driven by a turbine 4.

Further, a bypass passage 2a is connected to the exhaust passage 2 so as to bypass a portion where the turbine 4 is disposed, and a waste gate valve 6 for opening and closing the bypass passage 2a is provided in the bypass passage 2a.

Furthermore, a pressure-responsive actuator 7 for driving the waste gate valve 6 to open and close is provided.
This actuator 7 has, in its casing,
It has a first diaphragm 9 and a second diaphragm 10 of the same diameter, the first diaphragm 9 being connected to the waste gate valve 6 via the first rod 8, and the second diaphragm 10 being connected to and separating from the first diaphragm 9. is connected to a possible second rod 15.

The actuator 7 also includes a first return spring 13 with a large set load and a second return spring 14 with a small set load, and the first return spring 13 is loaded between the casing and the first diaphragm 9. By this, the waste gate valve 6 is biased in the closing direction via the first diaphragm 9 and the first rod 8, and the second
The return spring 14 is loaded between the casing and the second diaphragm 10 to
The second rod 15 is urged through the diaphragm 10 in a direction to separate it from the first diaphragm 9.

Furthermore, the actuator 7 has a first pressure chamber 11
and a second pressure chamber 12, the first pressure chamber 11 is formed between the first diaphragm 9 and the second diaphragm 10, and the second pressure chamber 12 is formed between the second diaphragm 9 and the second diaphragm 10.
It is formed adjacent to the first pressure chamber 11 with the diaphragm 10 in between.

Incidentally, a first control passage 16 is connected to the first pressure chamber 11, and a pressure passage 19 as a second control passage is connected to the second pressure chamber 12.

The first control passage 16 is connected to an atmospheric passage 17 and a pressure passage 19 via a solenoid valve 18 as an electromagnetic switching valve.
and is connected to.

The atmospheric passage 17 is connected to the compressor upstream intake passage section 1a, and the pressure passage 19 is connected to the compressor downstream intake passage section 1b. As a result, atmospheric pressure is introduced through the atmospheric passage 17, and compressor downstream pressure in the intake passage 1 is introduced through the pressure passage 19.

The solenoid valve 18 also includes a solenoid coil 18a that receives a signal from the controller 20, and when the solenoid coil 18a is excited, the plunger 18b moves the return spring 18.
When the solenoid coil 18a is de-energized, the plunger 18b is pushed by the return spring 18c, thereby introducing atmospheric pressure into the first control passage 16. The pressure on the downstream side of the compressor is introduced into 16. In this way, atmospheric pressure or compressor downstream pressure is selectively introduced into the first pressure chamber 11 through the first control passage 16, and the pressure passage 19 is introduced into the second pressure chamber 12.
Pressure downstream of the compressor is introduced through the compressor.

The controller 20 receives signals from a knock sensor 21, an air flow sensor 23, and an engine sensor 22 that detects engine load conditions, engine speed, water temperature, etc., and outputs a signal for de-energizing the plunger 18b. Consists of an input/output interface or memory.

In addition, the reference numeral 24 in FIG. 1 is an intercooler, 2
5 indicates a throttle valve.

With the above-described configuration, when the solenoid coil 18a is demagnetized and compressor downstream pressure is applied to the first pressure chamber 11 similarly to the second pressure chamber 12, the load in the closing direction of the wastegate valve 6 becomes the first
It is only necessary to consider the return spring 13, and as a result, the first diaphragm 9 substantially has the supercharging pressure characteristics as shown by the symbol A in FIG.
It operates as an actuator with only one. However, when the solenoid coil 18a is energized,
When atmospheric pressure is applied to the first pressure chamber 11, in this case, the load in the closing direction of the waste gate valve 6 must be taken into account from both the first return spring 13 and the second return spring 14. A supercharging pressure characteristic as shown by the symbol B in FIG. 2 can be obtained, and as a result, the supercharging pressure is controlled to be high.

From a different perspective, as shown in FIG. 3, the boost pressure-engine rotational speed characteristics of this engine can be set as indicated by symbols a and b.

Here, characteristic a indicates the case where compressor downstream pressure is introduced into the first pressure chamber 11 to make the pressure acting on the first pressure chamber 11 and the second pressure chamber 12 the same, and characteristic b indicates the case where the pressure acting on the first pressure chamber 11 and the second pressure chamber 12 is made the same. The case where atmospheric pressure is introduced into the pressure chamber 11 is shown. In this engine, even if the actuator 7 malfunctions, it can be kept within the range indicated by d in FIG. On the other hand, in the conventional system described above, there is a risk that the supercharging pressure may rise abnormally, as shown by the symbol c in FIG.

Therefore, in actual engine control, atmospheric pressure is introduced into the first pressure chamber 11, for example, in the early stages of acceleration where knocking is unlikely to occur (when accelerating when the engine combustion chamber temperature is below a predetermined value). hand,
By selecting supercharging pressure characteristic B, the supercharging pressure is increased compared to during steady high-load operation. This provides outstanding acceleration performance.

However, during steady high-load operation where the amount of ignition timing retard due to knocks exceeds a certain value and continues, specifically when driving with high boost pressure characteristic B, if knocks begin to occur, the first pressure chamber By introducing compressor downstream pressure into the compressor 11, making the pressures in the first pressure chamber 11 and the second pressure chamber 12 the same, and selecting the other boost pressure characteristic A, the knock and exhaust temperature (exhaust temperature) can be adjusted. steps are taken to avoid an increase in

In this way, even if the actuator 7 is activated by mistake, the supercharging pressure will not increase abnormally, and outstanding acceleration performance can be achieved in the early stages of acceleration, and no knocks will occur in the steady high-load operation range. This makes it possible to reliably prevent the exhaust temperature from rising.

Note that as the actuator, those shown in FIGS. 4 and 5 can be used. In the actuator 7' shown in Fig. 4, the first diaphragm 9' has a larger area than the second diaphragm 10', and conversely, in the actuator 7'' shown in Fig. 5, the second diaphragm 10'' has a larger area. 1 diaphragm 9''. By changing the diameter between the diaphragms in this way, the one shown in FIG. 4 will have the supercharging pressure characteristics A', as shown in FIG.
B' (characteristic A' is the one in which compressor downstream pressure is introduced into the first pressure chamber 11', and characteristic B' is the one in which atmospheric pressure is introduced into the first pressure chamber 11'), as shown in Fig. 5. In the case shown in Fig. 7, the boost pressure characteristics A'' and B'' (characteristic A'' is the one when compressor downstream pressure is introduced into the first pressure chamber 11'',
B'' is when atmospheric pressure is introduced into the first pressure chamber 11'')
can be obtained.

Also, if the area between the diaphragms is changed, the third
The slopes of characteristics a and b in the figure also change.

In Figs. 4 and 5, 8' and 8'' are the first rods, 12' and 12'' are the second pressure chambers, 13' and 13'' are the first return springs, and 14' and 14'' are the second rods. The return springs 15', 15'' designate second rods, each member of which performs substantially the same function as each member of the previous embodiment shown without a dash.

As detailed above, according to the supercharged engine of the present invention, the supercharger includes a turbine disposed in the exhaust passage and a compressor disposed in the intake passage and driven by the turbine. In addition, a bypass passage connected to the exhaust passage to bypass the part where the turbine is installed, a waste gate valve that opens and closes the bypass passage, and a pressure-responsive actuator that opens and closes the waste gate valve. In the engine,
The actuator closes a first diaphragm connected to the waste gate valve via a first rod, a second diaphragm connected to a second rod that can be moved into and out of the first diaphragm, and closes the waste gate valve. a first return spring that urges the second rod in a direction that separates the second rod from the first diaphragm; and a second return spring that urges the second rod away from the first diaphragm; and a second pressure chamber formed adjacent to the first pressure chamber via the second diaphragm, and the first pressure chamber is provided with atmospheric pressure or a pressure downstream of the compressor in the intake passage. A first control passage with a switching valve that can selectively introduce side pressure is connected, and a second control passage that can introduce compressor downstream pressure in the intake passage into the second pressure chamber.
When the control passage is connected and compressor downstream pressure is acting on the first pressure chamber due to the action of the switching valve, if the pressure in the first pressure chamber exceeds the first set positive pressure, the first When the diaphragm operates to open the waste gate valve against the biasing force of the first return spring and atmospheric pressure is acting on the first pressure chamber due to the action of the switching valve, the second When the pressure in the pressure chamber exceeds the second set positive pressure, the second diaphragm is activated by the biasing force of the first return spring and the second set positive pressure.
Since the waste gate valve is operated to open the waste gate valve through the second rod and the first diaphragm against the biasing force of the return spring, atmospheric pressure is applied to the first pressure chamber by the action of the switching valve. The first supercharging pressure characteristic (in the example, ) is obtained, and when compressor downstream pressure (i.e. supercharging pressure) acts on the first pressure chamber due to the action of the switching valve, supercharging in the first pressure chamber is increased. The second supercharging pressure characteristic (in the embodiment, the maximum supercharging pressure is set to be low) is obtained based on the magnitude relationship between the pressure and the biasing force of the first spring, and the switching valve By controlling this, it is possible to obtain a plurality of types of maximum supercharging pressure characteristics based on operating conditions and the like during supercharging.

[Brief explanation of drawings]

The figures show a supercharged engine as an embodiment of the present invention. Figure 1 is its overall configuration, Figures 2 and 3 are graphs for explaining its operation, and Figures 4 and 5 are graphs for explaining its operation. The figure is a schematic diagram showing a modification of each actuator, and FIGS. 6 and 7 are graphs for explaining the actions of those shown in FIGS. 4 and 5, respectively. DESCRIPTION OF SYMBOLS 1... Intake passage, 1a... Compressor upstream side intake passage part, 1b... Compressor downstream side intake passage part, 2... Exhaust passage, 2a... Bypass passage, 3... Turbocharger (supercharger), 4... Turbine, 5...
Compressor, 6...wastegate valve, 7,
7′, 7″…actuator, 8, 8′, 8″…first
Rod, 9,9',9''...first diaphragm, 1
0,10',10''...Second diaphragm, 11,1
1', 11''...first pressure chamber, 12, 12', 12''...
Second pressure chamber, 13, 13', 13''...first return spring, 14, 14', 14''...second return spring, 15, 15', 15''...second rod,
16...First control passage, 17...Atmospheric passage, 18...Solenoid valve, 18a...Solenoid coil, 18b
...Plunger, 18c...Return spring, 1
9... Pressure passage (second control passage), 20... Controller, 21... Knock sensor, 22... Engine sensor, 23... Air flow sensor, 24... Intercooler, 25... Throttle valve.

Claims (1)

[Claims] 1. A supercharger consisting of a turbine interposed in an exhaust passage and a compressor interposed in an intake passage and driven by the turbine, and connected to the exhaust passage in order to bypass the part where the turbine is installed. In the engine, the actuator is connected to the waste gate valve via a first rod. a first diaphragm connected to the first diaphragm, a second diaphragm connected to a second rod that can be moved into and out of the first diaphragm, a first return spring that biases the waste gate valve in the closing direction, and a second diaphragm connected to the second rod. a second return spring biasing the rod away from the first diaphragm; and a first return spring formed between the first diaphragm and the second diaphragm and separated from the atmosphere via the first diaphragm. a pressure chamber; and a second pressure chamber formed adjacent to the first pressure chamber via the second diaphragm; A first control passage with a switching valve that can selectively introduce pressure is connected, and a second control passage that can introduce compressor downstream pressure in the intake passage into the second pressure chamber.
When the control passage is connected and compressor downstream pressure is acting on the first pressure chamber due to the action of the switching valve, if the pressure in the first pressure chamber exceeds the first set positive pressure, the first When the diaphragm operates to open the waste gate valve against the biasing force of the first return spring and atmospheric pressure is acting on the first pressure chamber due to the action of the switching valve, the second When the pressure in the pressure chamber exceeds the second set positive pressure, the second diaphragm is activated by the biasing force of the first return spring and the second set positive pressure.
A supercharged engine, characterized in that the engine is configured to operate to open the waste gate valve via the second rod and the first diaphragm against the biasing force of a return spring.