JPS6024907Y2 - supercharging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust turbocharger particularly used in diesel engines.

In an exhaust turbo supercharger, the turbine is rotated by the engine's exhaust gas, and a compressor directly connected to it pressurizes the intake air and supplies it to the engine (supercharging). It is difficult to match the engine and the supercharger over the range of high speed rotations where the energy increases, and it has been difficult to provide sufficient supercharging, especially in low speed rotation and high load ranges where the exhaust energy is too small.

In order to solve the above problem, as shown in FIG.
15, in the range where it is desired to increase the overpressure air in the low speed rotation range, the valve 41 concentrates all the exhaust gas from the engine 3 onto one scroll 14, producing the same effect as throttling the turbine nozzle. The turbine 11 is rotated at a high speed, and when the engine speed increases and an appropriate boost pressure is required, exhaust gas is dispersed to each scroll 14 and 15 to maintain an appropriate boost pressure.

However, when transitioning from a state in which exhaust gas is concentrated on one scroll 14 to a state in which it is dispersed in each scroll 14.15, if the transition occurs suddenly, overpressure air (supercharging pressure) This causes a sudden drop in the amount of carbon dioxide, generating graphite and deteriorating engine performance.

In order to prevent this, as shown in FIG. 1, the valve 41 is attached to a diaphragm 42 that partitions a pressure chamber 43 on which the supercharging pressure acts and an atmospheric pressure chamber 44 on which a spring 45 is provided. The valve 41 was controlled by the balance between the pressure and the tension of the spring 46.

That is, as shown in FIG. 3, when the boost pressure reaches a predetermined pressure A, the valve 41 starts to lift from the seat 23, and as the boost pressure increases, the lift gradually increases. Exhaust gas is gradually introduced into the other scroll 15, and when the set pressure B reaches the set pressure B, which is higher than the pressure A, the lift is completely finished and each scroll 14 and 15
The system smoothes the transition from the concentrated state to the dispersed state of the exhaust gas so that it flows in an evenly distributed manner, thereby preventing a sudden drop in boost pressure associated with the transition.

By the way, the condition in which the exhaust gas is concentrated in one scroll 14 is necessary in low speed and high load ranges where overpressure air is insufficient because the exhaust energy is small; It is no longer necessary in the high-speed rotation range, where overpressure air becomes excessive due to medium loads or increased energy.

However, in the conventional device, the exhaust gas transfer (the start of lift of the valve 41) begins at a constant boost pressure A, so even if the rotation increases, the diagonal line (
The exhaust gas was concentrated on one scroll 14 as shown by E zone).

By the way, if the exhaust gas flows in a concentrated manner to only one scroll 14 in this way, the exhaust pressure increases, which increases the friction of the public engine and increases fuel consumption, which is undesirable.

As described above, the present invention ensures a smooth transition from a state in which the flow of exhaust gas to the exhaust turbocharger is concentrated on one scroll to a state in which it is dispersed in each scroll, thereby reducing the supercharging pressure. In the range where the concentration of exhaust gas is not required, i.e. at low speed rotation, low to medium load, and medium to high speed rotation, the flow is distributed to each scroll regardless of the boost pressure to slow down the friction. This is what I am trying to do.

The feature is that the pressure chamber of the valve control device of the valve that opens and closes the opening sheet formed in the partition wall that divides the turbine inlet into two according to the two scrolls is connected to the intake pipe and the pressure source via a switching solenoid valve. The switching solenoid valve is connected to a power source via a load switch that closes when the load exceeds a set load, and the pressure chamber is connected to the intake pipe side when the load switch is closed.

The present invention will be explained below with reference to an embodiment shown in FIG.

1 is an exhaust turbo supercharger, a turbine 11 and a compressor 12 thereof are connected by a shaft 13, and the turbine 11 is formed with two scrolls 14 and 15.

The turbine inlet is also divided into two parts 16 and 17 in line with the turbine scrolls 14 and 15.

Furthermore, the air flowing in from the compressor inlet 18 is pressurized by the compressor 12 and supplied to the engine 3 through the intake pipe 19, and the exhaust gas discharged from there is passed through the exhaust duct 20.
The air flows into the turbine inlet 16, 17 through the turbine, rotates the turbine 11, and is discharged from the turbine outlet 21.

4 is a valve control device, the valve 41 of which opens and closes an opening seat 23 provided on the partition wall 22 that extends the turbine inlets 16 and 17 independently from each other; the valve 41 is seated on the seat 23; If the valve 41 is lifted from the seat 23, the exhaust gas is distributed in two turbine inlets 16, 17. It is supposed to be done.

Further, the control device 4 has a pressure chamber 43 and an atmospheric pressure chamber 44, which are partitioned by a diaphragm 42 to which a valve 41 is attached. , and the valve 41 starts to open when the supercharging pressure reaches a predetermined supercharging pressure (A in Figure 3), and the setting is such that the pressure value is much larger than the supercharging pressure. A spring 45 is provided with a preset spring characteristic to complete the lift of the valve 41 at boost pressure (B in FIG. 3).

The pressure chamber 43 is connected to the intake pipe 19 via an inlet pipe 47 by switching a three-way solenoid valve 46 as a switching solenoid valve.
The supercharging pressure from the engine or the pressure from a pressure source 49 such as an air tank via a pressure pipe 48 is introduced.

Further, the electromagnetic valve 46 is connected to a control lever or a control rack of a fuel injection pump that responds to the engine load, and is connected to a power source 51 via a load switch 50 that closes its contacts when the load exceeds a set load, and when the load falls below a set load. When the load switch 50 is open, the pressure chamber 43
and the pressure source 49, the diaphragm 42 is bent against the spring 45, the valve 41 is completely lifted, the opening seat 23 is opened, and the load switch 50 is opened when the set load is exceeded.
In the closed state, the pressure chamber 43 and the intake pipe 19 are communicated with each other, and the operation of the valve 41 is controlled by the balance between the supercharging pressure and the spring 45.

That is, when the load exceeds the set load, the valve 41 seats on the seat 23 and supplies exhaust gas only to one scroll 14 until the predetermined boost pressure (A in FIG. 3) is reached where the boost pressure starts to overcome the spring force. Concentrate the flow, and then increase the lift as the supercharging pressure increases and move the flow to the other scroll 15.
In addition, as described above, the lift is completely completed at the set boost pressure (B in FIG. 3), which has a pressure value sufficient to completely complete the lift of the valve 41 against the spring force. Above that point, the flow is distributed equally to each scroll 14, 15.

In addition, the set load is a load near the point where the amount of air relative to the injected fuel starts to become excessive when the load is reduced at low speed rotation and the exhaust gas is distributed and flows into the two scrolls 14 and 15. , that is, the excess air ratio is 1.
It is desirable to set the load to around 5 to 2 (C in FIG. 3), but there is no limitation.

In the above configuration, the set load is set to C in Fig. 3 as described above.
To explain the operation as follows, when the load is lower than the set load C, the three-way solenoid valve 46 shuts off the pressure chamber 43 and the introduction pipe 47.
Since the pressure chamber 43 and the pressure pipe 48 are communicated with each other, pressure from the pressure source 49 is supplied to the pressure chamber 43, so the valve 41 is completely lifted and the exhaust gas is The flow will be distributed equally over the two scrolls 14.15.

Then, when the set load C is reached, the electromagnetic valve 46 cuts off the pressure chamber 43 and the pressure pipe 48 by closing the contacts of the load switch 50, and allows the pressure chamber 43 and the introduction pipe 47 to communicate with each other.

In this state, in the range where the boost pressure is below the predetermined pressure A (low speed rotation range), the valve 41 sits on the seat 23 and concentrates all the exhaust gas to only one scroll 14, so that the exhaust gas flows into this scroll 14. The flow rate of the exhaust gas increases and the turbine 11 rotates at high speed to increase the overpressure air.

When the engine speed increases and reaches a predetermined boost pressure A, the valve 41 begins to lift from the seat 23, and as the engine speed increases further, the lift gradually increases as the boost pressure increases accordingly. A gradual transition from a state in which the fluid flows into one scroll 14 to a state in which it flows in a distributed manner into the other scroll 15 prevents a sudden drop in supercharging pressure.

Further, when the engine speed increases and reaches the above-mentioned set supercharging pressure (B in FIG. 3), the valve 41 will finish lifting completely, and if the engine speed exceeds that point, the exhaust gas will flow through the two scrolls 14. The inflow will be distributed equally to 15.

As described above, the pressure chamber of the valve control device of the valve that opens and closes the opening seat formed in the partition wall that divides the turbine inlet into two in accordance with the two scrolls is connected to the intake pipe and the pressure source via the switching solenoid valve. According to the supercharging device of the present invention, the switching solenoid valve is connected to a power source via a load switch that closes when the load is higher than a set load, and the pressure chamber is connected to the intake pipe side when the load switch is closed. In the following conditions, the exhaust gas always flows in a distributed manner through the two scrolls 14 and 15, making it possible to lower the exhaust pressure within the shaded area in Figure 3 compared to the conventional system, thereby reducing the friction of the public institution. This makes it possible to improve fuel consumption.

In addition, when the load is higher than the set load, all the exhaust gas flows concentrated in one scroll b-14 in the low-speed rotation range, so the overpressure air increases, ensuring output in the low-speed range, and the rotation increases. At medium speed rotation or higher, two scrolls 1
4.15, the exhaust gas flows in an evenly distributed manner, preventing an abnormal increase in supercharging pressure.Furthermore, the valve 41 is gradually lifted when the exhaust gas is shifted from a concentrated state to a dispersed state. , a sudden drop in boost pressure is prevented.

In this embodiment, the pressure from the pressure source 49 is introduced into the pressure chamber 43 below the set load, the diaphragm 42 is bent against the spring 45, and the valve 41 is completely lifted from the seat 223. Alternatively, the atmospheric pressure chamber 44 may be connected to a negative pressure source, and the atmospheric pressure chamber 44 may be deflected by suction by negative pressure.

Similarly, in this embodiment, the diaphragm 42 is bent when the load is below the set value so that the exhaust gas is distributed equally to the two scrolls 14. Since the increase in exhaust pressure is also small, the engine rotation speed may be detected and the diaphragm 42 may be deflected at a rotation speed higher than that at which the exhaust pressure increases. It is preferable to use the rotation when the valve 41 finishes lifting in the C load state where the amount of air relative to the fuel is excessive, that is, the rotation at the intersection of the load C and the boost pressure B.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view showing a conventional supercharging device, Fig. 2 is a longitudinal cross-sectional view showing an embodiment of the present invention, and Fig. 3 is a graph of output vs. engine speed using supercharging pressure as a parameter. be. 1; exhaust turbo supercharger, 3; internal combustion engine, 4; knob control device, 11; turbine, 12; compressor, 14,
15; Scroll, 16.17; Turbine inlet, 19;
Intake pipe, 20; exhaust duct, 41; valve, 42; diaphragm, 43: pressure chamber, 44; atmospheric pressure chamber, 45; spring, 17; introduction pipe.

Claims (1)

[Scope of utility model registration request] The pressure chamber of the valve control device of the valve that opens and closes the opening seat formed in the partition wall that divides the turbine inlet into two in accordance with the two scrolls is connected to the intake pipe and the pressure source via a switching solenoid valve. A supercharging device that connects a valve to a power source via a load switch that closes the valve when the load exceeds a set load, and connects the pressure chamber to the intake pipe side when the load switch is closed.