JPH0751897B2 - Control device for turbocharger - Google Patents

Description

The present invention relates to a turbocharger control device that can be used in an exhaust turbocharger.

(Prior Art) The exhaust turbine supercharger proposed in Japanese Patent Laid-Open No. 60-128931 will be described with reference to FIG. 3. Exhaust gas inflow of a turbine 3 provided in an exhaust gas passage 2 of an engine 1 will be described. The passage 4 is configured as a plurality of passages, and these passages are divided into a low flow passage 5 and a high flow passage 6, and the high flow passage 6 is opened and closed according to the operating state of the engine 1. A control valve 7 to be controlled is provided, and a bypass passage 8 connected to the exhaust passage 2 downstream of the turbine 3 is provided in the low flow passage 5, and the bypass passage 8 is provided so that the boost pressure is equal to or less than a set value. The waste gate valve 9 controls the opening and closing of the exhaust gas. The waste gate valve 9 bypasses the exhaust gas when the boost pressure exceeds the upper limit set value to keep the boost pressure constant, and the control valve 7 rotates the engine. , Throttle opening, exhaust Based on the signal, such as, is opened or closed by a control circuit 10.

However, in the conventional device shown in FIG. 3, the wastegate valve 9 and the control valve 7 are independently controlled, so that the wastegate valve 9 operates even when exhaust gas is flowing only through the low flow passage 5. Therefore, there is a risk that the exhaust gas may be bypassed, the thermal efficiency of the supercharger may be reduced, and as a result, the fuel efficiency of the engine may be deteriorated.

(Problems to be Solved by the Invention) The present invention is intended to solve problems such as a decrease in thermal efficiency of a supercharger in a conventional exhaust turbine supercharger and a deterioration in fuel efficiency of an engine. .

[Structure of Invention]

(Means for Solving Problems) Therefore, the present invention is directed to a turbocharger having a compressor arranged in the middle of an intake passage of an internal combustion engine and a turbine arranged in the middle of an exhaust passage to rotate the compressor. In the feeder, a control valve that adjusts the diameter of the turbine inlet, a first actuator that controls the control valve based on a boost pressure in the intake passage downstream of the compressor, and an exhaust passage upstream of the turbine. A bypass passage communicating with the exhaust passage on the turbine downstream side, a wastegate valve opening / closing the bypass passage, and a second actuator opening / closing the wastegate valve based on the pressure in the exhaust passage upstream of the turbine And are provided as means for solving problems.

(Operation) At low engine speed, the control valve is controlled based on the supercharging pressure, so that the control valve is closed and the diameter of the turbine inlet is small. Next, as the engine speed increases and the boost pressure increases, the control valve opens and the turbine inlet diameter increases. When the engine speed further increases, the pressure on the upstream side of the turbine increases, so the wastegate valve is opened by the second actuator and the exhaust gas on the upstream side of the turbine escapes to the downstream side of the turbine via the bypass passage. . As a result, the supercharging pressure is maintained constant and the pressure increase on the upstream side of the turbine is suppressed.

EXAMPLES Examples of the present invention will be described below with reference to the drawings. FIG. 1 and FIG. 2 show different examples of the present invention. First, referring to FIG. 1, 11 is a supercharger, 12 is a low flow passage, 13 is a high flow passage, 14 is a control valve, and 15 is a wastegate valve. The control valve 14 is opened / closed by an actuator 18 with which the boost pressure 16 communicates with a communicating pipe 17, and the waste gate valve 15 is switched via a solenoid valve 20 capable of switching between the boost pressure 16 and the air cleaner 19. It is opened and closed by an actuator 21 controlled by the supercharging pressure and the atmosphere.
The solenoid valve 20 is driven by a pressure switch 23 whose electric contact is interrupted by a supercharger inlet pressure 22.

The operation will be described below. When the engine speed is low and the flow rate is low, the pressure in the diaphragm chamber 18a of the actuator 18 is low, the control valve 14 is closed by the spring 18b, and only the low flow rate passage 12 is fed. Next, as the rotation increases, the boost pressure 16 also increases, the control valve 14 opens against the spring 18b, and exhaust gas also flows into the high flow passage 13. When the inlet pressure 22 exceeds the set pressure of the pressure switch 23 due to further high rotation and high load, the solenoid valve 30 is energized and the supercharging pressure is applied to the diaphragm chamber 21a of the actuator 21. Therefore, the waste gate valve 15 opens, letting out exhaust gas,
The supercharging pressure is kept constant and the inlet pressure 22 is prevented from rising too much.

Next, another embodiment shown in FIG. 2 will be described. This embodiment shows that the pressure switch 23 and the solenoid valve 20 in the embodiment shown in FIG.
Is replaced with one pressure switching valve 24.
The state shown in the figure shows the case where the inlet pressure 22 is low.
25 is pushed to the right side to open the atmosphere port, and the atmosphere is communicating with the actuator 21.

Next, when the inlet pressure 22 rises, the pressure in the diaphragm chamber 26 rises and pushes the valve 25 to the left against the spring 27, so that the boost pressure 16 is applied to the actuator 21,
The wastegate valve opens via the link mechanism. Although the diaphragm is used as the actuator in each of the above-described embodiments, these may be replaced with a step motor or the like.

〔The invention's effect〕

As described in detail above, according to the present invention, the control valve is closed when the engine speed is low, and the turbine inlet diameter is small. When the engine speed is high, the control valve is open and the turbine inlet diameter is increasing. When the engine speed becomes higher, the wastegate valve opens and exhaust gas escapes to the bypass passage. Therefore, the supercharging pressure is always kept constant, and the rise of the pressure on the upstream side of the turbine is suppressed.

[Brief description of drawings]

1 and 2 are system diagrams of a control device for a turbocharger showing different embodiments of the present invention, and FIG. 3 is a system diagram of a conventional exhaust turbine supercharger. Description of main parts of the figure 11 …… Supercharger 12 …… Low flow passage 13 …… High flow passage 14 …… Control valve 15 …… Wastegate valve 16 …… Supercharging pressure 17 …… Communication pipe 18,21… … Actuator 22 …… Supercharger exhaust inlet pressure

Claims (1)

[Claims] 1. In a turbocharger having a compressor arranged in the intake passage of an internal combustion engine and a turbine arranged in the exhaust passage to rotate the compressor, the diameter of the turbine inlet is adjusted. Control valve, a first actuator that controls the control valve based on the supercharging pressure in the intake passage on the downstream side of the compressor, and the exhaust passage on the turbine upstream side and the exhaust passage on the turbine downstream side communicate with each other. A turbo valve, comprising: a bypass passage, a wastegate vibrator for opening and closing the bypass passage, and a second actuator for opening and closing the wastegate valve based on the pressure in the exhaust passage upstream of the turbine. Feeder control device.