What is the function of the exhaust bypass valve on the turbocharger? What are its control methods?
Nowadays, more and more small-displacement turbocharged engines are used in automobiles. Its advantage is that it can greatly increase the power and torque of the engine without increasing the engine displacement. However, turbochargers also have major shortcomings: at low speeds, the supercharging is insufficient and the turbo lags; and at high speeds, there will be overcharging. In order to overcome such shortcomings, a bypass valve is designed on the supercharger to control the boost pressure of the turbocharger actuator manufacturer.
Turbocharger actuator manufacturers
1. The working principle of the bypass valve turbocharger:
At high speed and high load, the turbocharger bypass valve is opened, and part of the exhaust gas enters the exhaust pipe directly through the bypass valve, and a part of the exhaust gas is released, and the turbine speed drops to control the boost pressure.
There are two control methods for the bypass valve turbocharger, one is mechanical (vacuum) control, usually used in truck diesel engines; the other is electronic control, usually used in cars.
2. The structure and working principle of mechanical control bypass valve
The mechanical control bypass valve is mainly composed of a control air chamber, a tie rod, and a bypass valve. The left side of the diaphragm in the bypass valve actuator passes pressurized gas.
1. When the engine is running at low speed, the outlet pressure of the compressor is low, the bypass valve is closed under the action of the return spring, and the exhaust gas discharged from the engine passes through the turbine end of the supercharger, thereby increasing the speed of the turbine. Larger intake pressure increases the intake air volume and improves the low-speed performance of the engine.
2. When the engine is running at high speed, the boosted gas pressure exceeds the specified value. The boosted gas will lift the diaphragm in the exhaust actuator, drive the bypass valve lever to move, and open the exhaust bypass valve. Part of the exhaust gas does not pass through the turbine end of the supercharger, but is directly discharged into the atmosphere from the exhaust bypass channel, so that the turbine inlet flow rate is reduced, the pressure is reduced, the speed of the supercharger is reduced, and the pressure of the boost is reduced.
3. The structure and working principle of the electronic control bypass valve
The opening and closing of the exhaust bypass valve is controlled by the boost pressure control solenoid valve controlled by the electronic control unit ECU. The electronic control unit ECU monitors the working conditions of the engine, compares it with the internal preset parameters, and controls the opening time of the solenoid valve accordingly, so as to change the opening of the exhaust bypass valve, control the exhaust bypass, and accurately The purpose of adjusting boost pressure.
4. Precautions for the use of bypass valve turbocharger:
1. The setting and verification of the preload pressure of the spring in the bypass valve actuator is carried out on the special setting and verification equipment of the manufacturer, and the user cannot adjust or change it at will.
2. Do not use the push rod and other parts installed outside the bypass valve supercharger assembly as a handle to move the supercharger assembly, so as not to affect the sensitivity and reliability of the bypass valve actuator.
Nowadays, more and more small-displacement turbocharged engines are used in automobiles. Its advantage is that it can greatly increase the power and torque of the engine without increasing the engine displacement. However, turbochargers also have major shortcomings: at low speeds, the supercharging is insufficient and the turbo lags; and at high speeds, there will be overcharging. In order to overcome such shortcomings, a bypass valve is designed on the supercharger to control the boost pressure of the turbocharger actuator manufacturer.
Turbocharger actuator manufacturers
1. The working principle of the bypass valve turbocharger:
At high speed and high load, the turbocharger bypass valve is opened, and part of the exhaust gas enters the exhaust pipe directly through the bypass valve, and a part of the exhaust gas is released, and the turbine speed drops to control the boost pressure.
There are two control methods for the bypass valve turbocharger, one is mechanical (vacuum) control, usually used in truck diesel engines; the other is electronic control, usually used in cars.
2. The structure and working principle of mechanical control bypass valve
The mechanical control bypass valve is mainly composed of a control air chamber, a tie rod, and a bypass valve. The left side of the diaphragm in the bypass valve actuator passes pressurized gas.
1. When the engine is running at low speed, the outlet pressure of the compressor is low, the bypass valve is closed under the action of the return spring, and the exhaust gas discharged from the engine passes through the turbine end of the supercharger, thereby increasing the speed of the turbine. Larger intake pressure increases the intake air volume and improves the low-speed performance of the engine.
2. When the engine is running at high speed, the boosted gas pressure exceeds the specified value. The boosted gas will lift the diaphragm in the exhaust actuator, drive the bypass valve lever to move, and open the exhaust bypass valve. Part of the exhaust gas does not pass through the turbine end of the supercharger, but is directly discharged into the atmosphere from the exhaust bypass channel, so that the turbine inlet flow rate is reduced, the pressure is reduced, the speed of the supercharger is reduced, and the pressure of the boost is reduced.
3. The structure and working principle of the electronic control bypass valve
The opening and closing of the exhaust bypass valve is controlled by the boost pressure control solenoid valve controlled by the electronic control unit ECU. The electronic control unit ECU monitors the working conditions of the engine, compares it with the internal preset parameters, and controls the opening time of the solenoid valve accordingly, so as to change the opening of the exhaust bypass valve, control the exhaust bypass, and accurately The purpose of adjusting boost pressure.
4. Precautions for the use of bypass valve turbocharger:
1. The setting and verification of the preload pressure of the spring in the bypass valve actuator is carried out on the special setting and verification equipment of the manufacturer, and the user cannot adjust or change it at will.
2. Do not use the push rod and other parts installed outside the bypass valve supercharger assembly as a handle to move the supercharger assembly, so as not to affect the sensitivity and reliability of the bypass valve actuator.
コメント