JPS62126224A - Supercharger - Google Patents

Abstract

PURPOSE:To improve the supercharging property and realize a high efficiency, by furnishing a variable vane added to a switch valve and a bypass valve to control a large flow route and a small flow route. CONSTITUTION:In a low engine operations, a switch valve 5 is closed and the exhaust gas flows through an exhaust gas passage 4c. A variable vane 10 has then a smaller area of nozzle section, and the speed of the exhaust gas flowing to turbine blades 7 is increased. As the engine rotation is increased gradually, the supercharging pressure increases to drive an actuator 9b to increase the nozzle area of the variable vane 10. As the engine rotation is further increased, an actuator 9 is driven by the supercharging pressure, the switch valve 5 is opened, and the exhaust gas flows into an exhaust gas passage 4b too. As the engine rotation is increased from a middle speed to a high speed, an actuator 9a is driven by the supercharging pressure, an exhaust gas bypass valve 15 is opened, and a part of the exhaust gas is released to the atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an engine supercharger, and particularly to a variable capacity supercharger suitable for improving efficiency from low to medium engine speeds.

[Background of the invention]

As described in U.S. Pat. No. 3,270,495, the conventional turbine case of a variable displacement supercharger has an exhaust gas passage divided into two and has a switching system, which allows the supercharging pressure to rise from low engine speeds. It is being

However, in this method, the inflow angle and inflow speed of the exhaust gas flowing into the turbine wheel are determined by the nozzle width and the amount of exhaust gas, so it is not possible to obtain optimal boost pressure characteristics and efficiency.

[Purpose of the invention]

An object of the present invention is to provide a variable capacity supercharger that has optimal boost pressure characteristics and efficiency from low to medium engine speeds.

[Summary of the invention]

The work of the supercharger is obtained from the energy of the exhaust gas, but if the exhaust gas passage and nozzle area are fixed, the exhaust gas flow angle and flow speed into the turbine wheel are determined by the exhaust gas volume at that time. It will be done. Therefore, depending on the amount of exhaust gas and the state of supercharging pressure, the exhaust gas inflow angle and inflow speed may not be in the optimal state for performing work, resulting in deterioration of efficiency. In order to solve this problem, a variable capacity turbine case has been devised in which the exhaust gas passage is divided into two by a partition wall, one for large flow rate and one for small flow rate. However, similar problems arise when trying to obtain an even more optimal boost pressure at low engine speeds. Therefore, in order to obtain optimum boost pressure and high efficiency even at low engine speeds, in the present invention, a variable vane is provided in the nozzle portion on the side with a smaller cross-sectional area of the exhaust gas passage. By moving the variable vane, the nozzle cross-sectional area and exhaust gas inflow angle can be controlled. Variable vanes can be activated depending on the amount of exhaust gas and boost pressure to create the optimal conditions at that time.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a conventional embodiment in which air is sent to the compressor 1.
is compressed and supplied to the engine 2. Exhaust gas is discharged from the engine 2, passes through an exhaust manifold 3, and is communicated to a turbine case 4. The turbine case 4 is divided by a partition wall 4a into a large exhaust gas passage 4b and an exhaust gas passage/J% 4Q, and a switching valve 5 is provided at the inlet. When the amount of exhaust gas is small at low engine speeds, the switching valve is sealed and the exhaust gas is
The air is guided through the nozzle section 6, drives the turbine wheel 7, and is emitted into the atmosphere through the muffler 8. When the engine is running at high speed, the boost pressure increases and the amount of exhaust gas increases, but in this case,
The switching valve 5 is opened by the actuator 9 which detects an increase in boost pressure, and the exhaust gas flow is also guided to the exhaust gas passage 4b, drives the turbine wheel 7, and then is discharged to the atmosphere.

Although not shown in this figure, a bypass valve is provided in the large exhaust gas passage 4b, and the bypass passage is communicated with the turbine case outlet to release a part of the exhaust gas to the atmosphere without driving the turbine wheel. Some embodiments include a bypass mechanism.

Next, an embodiment according to the present invention is shown in FIGS. 2 and 3. In this example, compared to the conventional example, the turbine case exhaust gas passage small 4
The six variable vanes 10 provided in the nozzle portion c are connected to a shaft 11, and connected to a link 12 and a ring 13. Ring 13 is connected to actuator 9b by link 14. The actuator 9b is communicated with the compressor 1 and is operated by boost pressure.

FIG. 4 is a view taken along arrow AA in FIG. 3, and the variable vane is
The link mechanism allows the cross-sectional area to be changed to a large cross-sectional area 14a and a cross-sectional area wheel 4c as shown in the figure, and the angle can be changed to α and β.

The operation at low engine speed will be explained below. Since the boost pressure is lower than the preset pressure value, the actuator 9 that operates the switching valve 5 does not work, and the switching valve 5 is sealed.
The exhaust gas is communicated to the small exhaust gas passage 4C. At this time, the variable vane is brought into a state with a small nozzle cross-sectional area and a small angle by the actuator 9b which similarly operates according to a preset pressure value to drive the variable vane. Because the nozzle cross-sectional area is small, the speed at which the exhaust gas flows into the turbine wheel is increased even when the engine speed is low and the exhaust gas is low.

As the engine speed gradually increases, the boost pressure gradually increases, and this increase in pressure causes the actuator 9 to
b is further actuated to drive the variable vane. The nozzle cross-sectional area gradually increases, reducing exhaust resistance loss due to an increase in the amount of exhaust gas and ensuring the optimal nozzle cross-sectional area for the amount of exhaust gas at that time.

Furthermore, the engine speed increases, and the amount of exhaust gas decreases.
If the cross-sectional area of the exhaust gas passage is too small in a vehicle and the exhaust loss becomes large, the actuator 9 is actuated by the boost pressure at that time, the switching valve 5 is opened, and the large exhaust gas passage 4b is also opened. Exhaust gases are channeled to reduce exhaust losses.

When the engine speed further increases from medium speed to high speed, the actuator 9a is activated by the supercharging pressure at that time, the exhaust bypass valve 15 is opened, and a portion of the exhaust gas is released to the atmosphere.

According to this embodiment, an efficient supercharging characteristic with little exhaust loss can be obtained, especially when the engine speed is low, and there is an effect of improving the engine output.

In addition, the same effect can be obtained by using a stepping motor instead of the actuator that drives the variable vane.

[Effects of the Invention] According to the present invention, the cross-sectional area of the exhaust gas passage nozzle portion is changed from low to medium engine speeds, and the inflow speed and inflow angle of the exhaust gas flowing into the turbine wheel are adjusted according to the engine state at that time. This has the effect of improving boost pressure characteristics and providing a highly efficient variable capacity supercharger.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a conventional variable capacity supercharger, Fig. 2 is a system diagram of a variable capacity supercharger according to an embodiment of the present invention, and Fig. 3 is a system diagram of a variable capacity supercharger according to an embodiment of the present invention. Figure 4 is an enlarged view of the feeder turbine case. FIG. 3 is a view taken along arrow AA in FIG. 3; 1... Compressor, 4... Turbine case, 5...
...Switching valve, 7...Turbine blade, 9...Actuator. ,! Nii Agent Patent Attorney Katsuma Ogawa
〜、／゛Figure 1 Figure 2

Claims (1)

[Claims] 1. A turbine wheel driven by exhaust gas, a compressor wheel located on the same axis as the turbine wheel, a bearing box located between the turbine wheel and the compressor wheel, and a bearing that encloses the compressor wheel. It has a compressor case connected to the box, and a turbine case connected to the bearing box, surrounding the turbine impeller, and connected to the exhaust manifold of the engine. is divided into two parts, large and small, and has an on-off valve near the inlet on the side with a large cross-sectional area of the exhaust gas passage of the turbine case, and also has a part of the exhaust gas on the side with a large cross-sectional area of the exhaust gas passage. 1. A supercharger having a bypass passage communicating with a turbine case outlet and a bypass valve, characterized in that a movable vane is provided in a nozzle portion on the side with a smaller cross-sectional area of the turbine case exhaust gas passage.