JPH0513964Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) This invention relates to the improvement of a supercharged engine installed in a vehicle such as an automobile.

(Prior Art) Generally, a supercharged engine is known as an engine installed in a vehicle such as an automobile. As shown in FIG. 4, this supercharged engine has a turbine 4 of the supercharger 3 in the exhaust passage 2 of the engine body 1, and a compressor 6 of the supercharger 3 in the air supply passage 5 of the engine body 1. It is set up.
In this case, the turbine 4 and compressor 6 of the supercharger 3 are mounted coaxially. When the engine body 1 is driven, the exhaust gas flow in the exhaust passage 2 of the engine body 1 causes the turbine 4 of the supercharger 3 to
As the turbine 4 rotates, the compressor 6 is also rotated to supercharge the air in the air supply passage 5 of the engine body 1. Therefore, as the exhaust gas flow increases, the air supply pressure in the air supply passage 5 of the engine body 1 also increases, so if left as is, there is a problem that the supercharging pressure (boost pressure) will rise too much.
If the supercharging pressure in the air supply passage 5 of the engine body 1 increases too much in this way, problems such as knocking are likely to occur in a gasoline engine, for example.

Therefore, a bypass passage 7 connected in parallel to the turbine 4 is provided in the exhaust passage 2 of the engine body 1, and a waste gate valve 8 is interposed in the bypass passage 7. When the supercharging pressure in the engine body 1 is lower than the set pressure, the bypass passage 7 is kept closed by the waste gate valve 8, thereby reducing the flow of exhaust gas discharged from the exhaust passage 2 of the engine body 1. All are guided to the turbine 4 side of the supercharger 3, and the air supply passage 5
It is designed to increase the boost pressure inside the engine. In addition, when the boost pressure in the air supply passage 5 exceeds the set pressure, the waste gate valve 8 of the bypass passage 7
is opened and a part of the exhaust gas flowing from the exhaust passage 2 of the engine body 1 to the turbine 4 side is released to the downstream side of the turbine 4 via the bypass passage 7. The system is designed to prevent the supercharging pressure from increasing too much and reduce the maximum pressure (Pmax) in the cylinder of the engine body 1, thereby reducing noise and pumping loss, and improving the fuel consumption rate (fuel efficiency). was.

However, in the case of the conventional structure described above, the temperature of the intake air flowing through the air supply passage 5 of the engine body 1 is maintained at a relatively low temperature, approximately the same temperature as the outside air temperature. At the time of low-temperature starting, there was a possibility that the temperature rise of the engine body 1 would be easily suppressed by the intake air in a low-temperature state. Therefore, it takes time to warm up the engine body 1, which poses a problem in improving the startability of the engine body 1.

(Problems to be solved by the invention) In the conventional configuration, the temperature of the intake air flowing through the air supply passage 5 of the engine body 1 is maintained at a relatively low temperature, approximately the same temperature as the outside air temperature. Therefore, when the engine body 1 is started at a low temperature, there is a possibility that the temperature rise of the engine body 1 is likely to be suppressed by the intake air in the low temperature state.
It took a long time to warm up the engine, which caused problems in improving the startability of the engine body 1.

This idea was developed with a focus on the above-mentioned problems, and it is possible to finish the warm-up operation of the engine body in a short time, improve the startability of the engine body, and improve the starting performance of the engine body. It is an object of the present invention to provide a supercharged engine that can smoothly move from a normal operating state to a normal operating state.

[Structure of the invention] (Means for solving the problem) This invention is based on a wastegate valve in a bypass passage whose one end is connected in parallel to the turbocharger turbine, which is interposed in the exhaust passage of the engine body. An exhaust circulation path is connected to the downstream side and the other end is connected to the inlet side of the compressor of the supercharger, and an exhaust circulation control valve is provided to open and close this exhaust circulation path. Equipped with an operating state detection function that detects the operating state of the engine, the waste gate valve and exhaust circulation control valve are held open when the engine starts at a low temperature, and the waste gate is linked to the increase in engine cooling water temperature. A controller that controls the valve opening from fully open to fully closed and switches the wastegate valve to the normal open/close control state and the exhaust circulation control valve to the fully closed state at the end of the engine starting operation. It was established.

(Function) When the engine is warmed up, the waste gate valve and exhaust circulation control valve are held open, and the high-temperature exhaust gas exhausted from the engine is supercharged through the bypass passage and the exhaust circulation passage. By introducing high-temperature exhaust gas into the intake air sucked into the engine body,
In addition to increasing the temperature of the intake air to promote warm-up of the engine, the valve opening of the wastegate valve is controlled from fully open to fully closed in conjunction with the rise in engine cooling water temperature. The valve opening degree of the wastegate valve is smoothly moved to the fully closed state at the end of the starting operation.

(Embodiment) An embodiment of this invention will be described below with reference to FIGS. 1 to 3. FIG. 1 shows a schematic configuration of the entire supercharged engine, where 11 is the engine body, 12 is an exhaust passage of this engine body 11,
13 is an air supply passage of this engine body 11.
Further, 14 is a supercharger attached to the engine body 11. The turbine 15 of the supercharger 14 is interposed in the exhaust passage 12 of the engine main body 11, and the compressor 16 of the supercharger 14 is interposed in the air supply passage 13 of the engine main body 11.

Furthermore, the exhaust passage 12 of the engine body 11 is provided with a bypass passage 17 connected in parallel to the turbine 15 . Further, a waste gate valve 18 is interposed in this bypass passage 17, and the bypass passage 17 is opened and closed by this waste gate valve 18. In this case, the waste gate valve 18 is formed of, for example, an electromagnetic on-off valve that can control the opening and closing of the valve to an appropriate opening degree. This waste gate valve 18 is connected to a controller 19 formed by a microcomputer and its peripheral circuits.
The opening/closing operation is controlled by a control signal from. Furthermore, the controller 19 includes a rotational speed detector 20 that detects the rotational speed of the engine main body 11, a position detector 21 that detects the depression operation position of the accelerator pedal, a temperature sensor 22 that detects the cooling water temperature of the engine main body 11, and an engine A boost pressure detector 23 that detects supercharging pressure (boost pressure) in the air supply passage 13 of the main body 11 is connected to each of them.

On the other hand, one end of an exhaust circulation path 24 is connected to the bypass passage 17 on the downstream side of the waste gate valve 18 . The other end of the exhaust circulation path 24 is connected to the inlet side of the compressor 16 of the supercharger 14 in the air supply passage 13 of the engine body 11. Furthermore, an exhaust circulation control valve 25 is interposed in the exhaust circulation path 24, and the exhaust circulation control valve 25 opens and closes the exhaust circulation path 24. Further, the exhaust circulation control valve 25 is formed of, for example, an electromagnetic on-off valve. This exhaust circulation control valve 25 is connected to the controller 19 together with the waste gate valve 18.
The opening/closing operation is controlled by a control signal from the controller 19. In this case, when the engine main body 11 is operating, the controller 19 compares the detected water temperature from the temperature detector 22 with a preset cooling water temperature for normal operation. If it is detected that the water temperature detected by the temperature detector 22 is lower than the set cooling water temperature, the controller 19 determines that the engine body 11 is in a warm-up operation state, and the engine body 11 is warmed up. During warm-up operation, the waste gate valve 18 and the exhaust circulation control valve 25 are held fully open by the controller 19. Also,
When the detected water temperature from the temperature sensor 22 increases, the valve opening degree of the waste gate valve 18 changes continuously from fully open to fully closed in conjunction with the increase in the detected water temperature from the temperature sensor 22, as shown in FIG. At the same time, the exhaust circulation control valve 25 is kept fully open, and the water temperature detected by the temperature sensor 22 rises to the set cooling water temperature, causing the engine body 11 to gradually close. At the end of the starting operation, the wastegate valve 18
In the normal opening/closing control state, the exhaust circulation control valve 25
It is designed to switch each to the fully closed state. In this case, during normal operation of the engine body 11, the wastegate valve 18 is controlled to open and close by the controller 19 based on a detection signal from the boost pressure detector 23, for example. When the detected boost pressure is lower than a preset set pressure, the waste gate valve 18 is held in a closed state, and when the detected boost pressure from the boost pressure detector 23 reaches the set pressure or higher, The waste gate valve 18 is operated to open.

Next, the operation of the above configuration will be explained. First, when starting the engine body 11, the temperature detector 2
Since it is detected that the cooling water temperature of the engine body 11 detected by the controller 2 is lower than the preset cooling water temperature during normal operation, the controller 19 starts the warm-up operation of the engine body 11. It is judged that the condition. During warm-up operation of the engine body 11, the controller 19 controls the waste gate valve 18 and the exhaust circulation control valve 25.
are held open, so that part of the exhaust gas flowing from the exhaust passage 12 of the engine body 11 to the turbine 15 side is released to the downstream side of the turbine 15 via the bypass passage 17, and
A portion of the exhaust gas flowing through the bypass passage 17 flows into the intake passage of the compressor 16 of the supercharger 14 in the air supply passage 13 of the engine body 11 via the exhaust circulation passage 24 . Therefore, the engine body 11
Since the high-temperature exhaust gas discharged from the engine body 11 is mixed into the intake air flowing through the air supply passage 13 of the Engine operation can be promoted and warm-up operation of the engine body 11 can be completed in a short time. When the water temperature detected by the temperature sensor 22 rises, the valve opening degree of the waste gate valve 18 changes from the fully open state to the fully closed state in conjunction with the rise in the water temperature detected from the temperature sensor 22, as shown in FIG. The valve opening degree of the exhaust circulation control valve 25 is maintained in the fully open state while the exhaust circulation control valve 25 is gradually closed in a continuous state. Therefore, the valve opening degree of the waste gate valve 18 can be smoothly moved to the fully closed state at the end of the starting operation of the engine main body 11, and the switching operation of the engine main body 11 from the warm-up operating state to the normal operating state can be performed. It can be done smoothly. In addition, the temperature detector 22
When the detected water temperature rises to the set cooling water temperature and the starting operation of the engine body 11 is completed, the waste gate valve 18 is switched to the normal opening/closing control state, and the exhaust circulation control valve 25 is switched to the fully closed state. During normal operation of the engine body 11, the waste gate valve 18 is controlled to open and close by the controller 19 based on a detection signal from the boost pressure detector 23, for example, and the detected boost pressure from the boost pressure detector 23 is set in advance. If the pressure is lower than the set pressure, the waste gate valve 18 is kept closed, and when the boost pressure detected by the boost pressure detector 23 reaches the set pressure or higher, the waste gate valve 18 is opened. be done.

It should be noted that this invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of this invention.

[Effect of the invention] According to this invention, one end is connected to the downstream side of the waste gate valve in the bypass passage connected in parallel to the turbine of the supercharger interposed in the exhaust passage of the engine body, and the other end An exhaust circulation path is connected to the inlet side of the compressor of the supercharger, and an exhaust circulation control valve is provided to open and close this exhaust circulation path, and the operating state of the engine body is detected based on the engine cooling water temperature. Equipped with an operating state detection function, the waste gate valve and exhaust circulation control valve are kept open when the engine starts at a low temperature, and the waste gate valve is fully opened in conjunction with the rise in engine cooling water temperature. At the end of the starting operation of the engine body, the wastegate valve is controlled to be in the normal open/close control state.
A controller is installed to switch the exhaust circulation control valves to the fully closed state, allowing the warm-up of the engine to be completed in a short time.
The startability of the engine body can be improved, and the engine body can be smoothly moved from the starting operating state to the normal operating state.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of this invention. Figure 1 is a schematic diagram of the entire engine with a supercharger, and Figure 2 is the temperature of the cooling water in the engine when the engine is started at a low temperature. Figure 3 is a characteristic diagram showing the relationship between the temperature of the cooling water in the engine body and the valve opening of the exhaust circulation control valve when the engine is started at a low temperature. FIG. 4 is a schematic diagram of the entire conventional supercharged engine. 11...Engine body, 12...Exhaust passage, 1
3... Air supply passage, 14... Supercharger, 15... Turbine, 16... Compressor, 17... Bypass passage, 18... Waste gate valve, 19...
Controller, 22...Temperature detector, 24...Exhaust circulation path, 25...Exhaust circulation control valve.

Claims (1)

[Scope of utility model registration request] A supercharger equipped with a bypass passage connected in parallel to the turbocharger turbine installed in the exhaust passage of the engine body, and a wastegate valve for adjusting boost pressure that opens and closes this bypass passage. an exhaust circulation path having one end connected to the downstream side of the waste gate valve in the bypass passage and the other end connected to the intake passage side of the engine body; and an exhaust circulation control valve for opening and closing the exhaust circulation path. and an operating state detection function for detecting the operating state of the engine main body based on the cooling water temperature of the engine main body, and the waste gate valve and the exhaust circulation control valve are each in an open state when the engine main body is started at a low temperature. and controlling the valve opening degree of the waste gate valve from a fully open state to a fully closed state in conjunction with a rise in the cooling water temperature of the engine main body, and opening the waste gate valve at the end of the starting operation of the engine main body. A supercharged engine characterized in that a controller is provided for switching the exhaust circulation control valve between a normal opening/closing control state and a fully closed state.