JPS6245059Y2 - - Google Patents

Description

[Detailed explanation of the invention] (Field of industrial application) This invention involves installing a turbine in the exhaust gas passage of the engine, and using the output of this turbine to drive a compressor installed in the intake passage to mix gas into the engine. The present invention relates to an exhaust turbine supercharging device that supercharges air.

(Prior art) If the exhaust gas inflow passage of the turbine described above is set to a cross-sectional area that corresponds to the high load region of the engine, for example, the flow velocity of exhaust gas will not be sufficient in the low load region, making it impossible to obtain supercharging efficiency. Furthermore, if the cross-sectional area is set to correspond to the low load region of the engine, the turbine will act as exhaust resistance in the high load region, causing a decrease in output and engine trouble.

Therefore, in order to solve these problems, the turbine exhaust gas inflow passage has two passages, a low-load passage and a high-load passage, and the low-load passage is used in the low-load region of the engine. by doing,
By increasing the flow velocity of exhaust gas to drive the turbine and using a high-load passage in high-load areas, the turbine is free from exhaust resistance and can be used in a wide range of both high- and low-load areas. , has been developed to allow supercharging.

When the above-mentioned low-load passage and high-load passage are formed, the high-load passage is closed by the control valve in the low-load region, and the control valve of the high-load passage is opened in the high-load region, and Either close the low-load passage with a control valve, or, if the low-load passage is also used in a high-load area, open the control valve of this passage, and control the opening and closing of the control valve according to the load area. There is a need to.

The opening/closing control of the control valve described above can be performed by detecting the operating state of the engine from the amount of intake air, the negative pressure in the intake passage, the engine speed, etc., and controlling the opening/closing in accordance with the operating state. In this case, there are problems such as an increase in the number of control signals, which makes internal processing difficult and the circuit configuration complicated.

On the other hand, since the exhaust gas pressure in the exhaust passage generates a pressure corresponding to the operating state of the engine, a means for detecting the pressure of this exhaust gas with a pressure sensor and controlling the opening and closing of the control valve is disclosed in Japanese Utility Model Application Publication No. 50-8306. It is known for.

In the case of this conventional device, the exhaust gas pressure on the upstream side of the control valve is detected by a pressure sensor to control the opening and closing of the control valve. When the sensor detects that the exhaust gas pressure has increased, it opens the control valve that had closed the high-load passage, but at the moment this control valve opens, surrounding exhaust gas enters the high-load passage. Due to the inflow, the exhaust gas pressure drops rapidly, and the pressure sensor detects this and controls the control valve to close again.This situation is repeated, causing surging in the control valve, causing the control valve to shut down. The problem is that stable operation cannot be obtained.

(Purpose of the invention) The purpose of this invention is to create an exhaust turbine supercharging system that can provide stable operation of a control valve that controls the opening and closing of the low-load passage and the high-load passage formed in the exhaust gas inflow passage of the turbine. It's on offer.

(Structure of the invention) This invention forms the exhaust gas inflow passage of the turbine into a low-load passage and a high-load passage, and provides the high-load passage with a control valve for opening and closing the passage.
The exhaust turbine supercharging device is characterized in that the opening and closing of the control valve is controlled by a valve driving device that opens the control valve when the exhaust gas pressure downstream of the turbine is high and closes it when the exhaust gas pressure is low.

(Effects of the invention) According to this invention, the valve drive device opens the control valve when the exhaust gas pressure downstream of the turbine is high and closes it when it is low, so the opening and closing of the control valve can be controlled stably. Can be done. That is, when the exhaust gas hits the turbine, the exhaust gas is agitated and pressure fluctuations within a short period of time are smoothed out.

For this reason, the exhaust gas pressure changes smoothly and becomes stable in accordance with the operating state of the engine, so by driving the valve drive device with this stable exhaust gas pressure and controlling the opening and closing of the control valve, stable control can be achieved. Valve opening/closing control can be obtained, and supercharging corresponding to the operating state of the engine can be smoothly performed.

(Example) An example of this invention will be described in detail below based on the drawings.

The drawing shows an exhaust turbine supercharging system, and in FIG. 1, an engine 1 has a cylinder 2, a piston 3, and a cylinder head 4.
The intake port 5 is provided with an intake valve 6 and is connected to an intake passage 7, and the exhaust port 8 is provided with an exhaust valve 9 and connected to an exhaust passage 10.

The exhaust turbine supercharging device 11 includes a turbine (turbine wheel) 12, a turbine housing 13 housing the turbine 12, a turbine shaft 14 having the turbine 12 fixed to one end, and a compressor (compressor impeller) fixed to the other end of the turbine shaft 14. ) 15, it has a compressor housing 16 that houses this compressor 15, and the compressor 1
The air-fuel mixture inflow side of No. 5 is connected to the upstream side of the intake passage 7, and the air-fuel mixture outflow side of No. 5 is connected to the downstream side of the intake passage 7.

On the other hand, the exhaust gas inflow passage 17 of the turbine 12 is formed into a low load passage 18 and a high load passage 19, the opening side of which is connected to the upstream side of the exhaust passage 10, and the exhaust gas outflow passage 20 of the turbine 12 is connected to the upstream side of the exhaust passage 10. The side is connected to the downstream side of the exhaust passage 10.

The above-mentioned low-load passage 18 is such that when the engine 1 is operating in a low-load region, by using only this passage 18, a flow velocity of exhaust gas that can rotate the turbine 12 to the rotation speed of the low-load set value can be obtained. When the engine 1 is operating in a high load region, the high load passage 19 is formed with a passage cross section such that the above-mentioned low load passage 18 and this high load passage 19,
The cross section of the passage is formed such that a flow velocity of exhaust gas can be obtained to rotate the turbine 12 at a rotation speed of a high load set value.

A bypass passage 21 that bypasses the turbine 12 is communicated between the above-mentioned low-load passage 18 and the exhaust gas outflow passage 20.
1 includes a valve 23 of a waste gate valve 22.
is provided to control opening and closing of this passage 21,
Also, the pressure introduction pipe 24 of the waste gate valve 22
is open to the intake passage 7 downstream of the compressor 15. Therefore, when the boost pressure exceeds the upper limit set value, the waste gate valve 22 operates and opens the bypass passage 21, allowing exhaust gas to escape from the bypass passage 21 to the downstream of the turbine 12, thereby bringing the boost pressure within the set value. lower to

The aforementioned high load passage 19 is provided with a control valve 25 that opens and closes this passage 19.
is controlled to open and close by a diaphragm device 28 via a lever 26 and a rod 27, and a pressure introduction pipe 29 of the diaphragm device 28 is opened to the exhaust passage 10 downstream of the turbine 12, and a pressure introduction pipe 29 is opened to the exhaust passage 10 downstream of the turbine 12. is provided with a solenoid valve 30 that opens and closes this passage.

The above-mentioned solenoid valve 30 is controlled to open and close by a control circuit 31, and this control circuit 31 receives a water temperature signal detected by a water temperature sensor of the cooling water of the engine 1.

A boost pressure signal detected by a pressure sensor that detects the boost pressure downstream of the compressor 15.

A rotation speed signal that detects the rotation speed of engine 1 using a rotation sensor.

Throttle opening signal that detects the opening of the throttle valve using a throttle opening sensor.

Knock signal detected by the knock sensor when engine 1 knocks.

Exhaust gas temperature or catalyst temperature signal detected by the temperature sensor.

etc., and the aforementioned solenoid valve 30 is controlled to open and close based on these signals.

Exhaust turbine supercharging device 11 configured in this way
To explain the operation, exhaust gas discharged from the engine 1 flows through an exhaust passage 10 and an exhaust gas inflow passage 1.
When the exhaust gas is supplied to the turbine 12 via the turbine 7, the exhaust pulsation and fluctuations in exhaust gas pressure within a short time are smoothed out by the exhaust gas hitting the turbine 12. Even if the control valve 25 in the passage 19 opens or closes and the exhaust gas pressure at a partial position of the control valve 25 fluctuates temporarily, the turbine 12
The exhaust gas pressure in the exhaust passage 10 downstream of the turbine 12 is smoothed downstream and is not affected by fluctuations. Therefore, the exhaust gas pressure in the exhaust passage 10 downstream of the turbine 12 is a pressure that does not pulsate or fluctuate within a short time corresponding to the operating state of the engine 1. It becomes a change.

The aforementioned control valve 25 controls the low load region of the engine 1 under the control of the diaphragm device 28 based on the exhaust gas pressure downstream of the turbine 12 when the solenoid valve 30 opens the passage of the pressure introduction pipe 29 of the diaphragm device 28. It is closed in the high load area, and opened in the high load area, and its operating state is as shown in the operating line A in Fig. 2.
Opening/closing is controlled to the state shown in . In addition, the control valve 25
is controlled to be open above the operating line A and closed below it.

In addition, in a high load region of the engine 1, when the boost pressure of the compressor 15 exceeds the set value, the waste gate valve 22 operates to release exhaust gas from the bypass passage 21 to the downstream of the turbine 12, thereby increasing the boost pressure. to prevent it from exceeding the set value.

Furthermore, in the following state, the solenoid valve 30 is controlled by the control circuit 31, the pressure introduction pipe 29 is closed, and the opening/closing control of the control valve 25 is stopped. In other words, when the water temperature signal indicates a temperature below the set value and the engine temperature is low, and the boost pressure signal indicates that the engine has become higher than the set value in the low load region, the knock signal will cause the engine to knock. When these conditions occur, the control of the control valve 25 is temporarily stopped, the output of the engine 1 is lowered, and the reliability of the engine 1 is improved. Also, when the exhaust gas temperature or catalyst temperature signal indicates that it is lower than the set value, the opening/closing control of the control valve 25 is stopped to improve the processing capacity of the catalyst.

The operating state of the solenoid valve 30 described above is controlled to open and close as shown in the operating line B in FIG. Note that the solenoid valve 30 is in operation line B.
It is open above and closed below.

In addition, in the above-mentioned embodiment, in the high load region of the engine 1, both the low load passage and the high load passage 1 are used.
8 and 19, but the high load passage 19 is formed to have a cross-sectional area corresponding to high loads, and in the high load area of the engine 1, only this high load passage 19 is used, and the low load passage 18 is Control valve 2 to close
5 may be controlled to open and close.

Further, the control valve 25 is driven by a diaphragm device 28, which is connected to the control circuit 3 via a solenoid.
1 may be used to control opening and closing. In this case turbine 12
The downstream exhaust gas pressure is detected by a pressure sensor, and this signal is input to the control circuit 31 to control the solenoid.

In the configuration of this invention, the valve drive device corresponds to the diaphragm device 28 of the embodiment.

[Brief explanation of the drawing]

The drawings show an embodiment of this invention, and FIG. 1 is a cross-sectional configuration diagram of the engine. FIG. 2 is a diagram showing the operating states of the control valve and the solenoid valve. 1...Engine, 10...Exhaust passage, 11...
Exhaust turbine supercharging device, 12...Turbine, 15
... Compressor, 17 ... Exhaust gas inflow passage,
18...Low load passage, 19...High load passage,
25...Control valve, 28...Diaphragm device.

Claims (1)

[Claims for Utility Model Registration] The exhaust gas inflow passage of the turbine, which is interposed in the exhaust gas passage of the engine, is structured into a low load passage and a high load passage, and the passage is opened and closed to the high load passage. An exhaust turbine supercharging device comprising: a control valve for controlling the gas pressure; and a valve driving device that opens the control valve when the gas pressure downstream of the turbine is high and closes the control valve when the gas pressure is low.