Technical analysis of use and maintenance of engineering machinery supercharger
Exhaust gas turbochargers of different brands are widely used in various large and medium-sized diesel trucks,https://www.fcfuda.com/ flatbed trucks, dump trucks and various construction machinery. For example, the Shangchai 6135 diesel engine of the ZL-50 loader is equipped with GJ110 and J112 superchargers; the D6114 diesel engine of the PY-180 grader is equipped with a HIE supercharger; the Jiefang Engineering Wang dump truck is equipped with a WHIC supercharger; Steyr heavy-duty The car is equipped with Garrett superchargers and so on. They enable diesel engines to significantly increase power and torque under the condition of the same structural size, while reducing fuel consumption and exhaust pollution, especially in plateau areas. In the working process, the speed of the supercharger is as high as tens of thousands of revolutions per minute, and it runs under high exhaust temperature for a long time, so its working conditions are bad. In the use of the above-mentioned vehicles, the power drop and the increase in fuel consumption caused by the improper use of the turbocharger have occurred to varying degrees, which in turn led to a significant drop in operating efficiency and economic benefits. Based on the research on various failures of diesel exhaust turbochargers in engineering practice throughout the year, the author makes the following discussion on the causes of common failures and preventive measures.
1 Correct use of diesel engine
The first is the quality level of diesel oil. For low-supercharged diesel engines, diesel oil of no lower than CC grade should be used; for medium-supercharged diesel engines, diesel oil of no lower than CD grade should be used. The second is the viscosity grade of diesel engine oil. The appropriate viscosity grade should be selected according to the temperature conditions and the wear condition of the parts. The third is the cleanliness of diesel oil, because the rotor shaft of the exhaust turbocharger and its bearing (sleeve) are more precise. If the diesel oil is too dirty or deteriorated, impurities or abrasive particles will be brought into the turbocharger. It will accelerate the bearing wear, and if the lubricant film is not formed, the rotor shaft and the bearing will seize. Therefore, it is necessary to keep the oil clean, clean the oil filter frequently, and replace the damaged oil in time.
2 The correct way to start a cold car
After the vehicle is started, the diesel engine should be idle for a few minutes (depending on the engine temperature and the outside atmospheric temperature), the standby oil reaches a certain temperature and pressure, the flow performance is improved, and the turbocharger bearing is fully lubricated, the speed can be increased and the start Driving or putting into construction work, this is especially important when the outside temperature is low. For vehicles that have been parked for a long time (such as more than a few days), the turbocharger oil inlet pipe joint should be loosened before starting, and an appropriate amount of oil of the same brand as the oil pan should be added to the oil inlet to prevent poor lubrication during starting. The rotor shaft is ablated. Some users have experienced similar situations on the Jiefang Engineering Wang dump truck and on the Komatsu grader in Japan, and should be avoided as much as possible.
3 Correct flameout method
If a diesel engine is running at high speed, if it suddenly turns off, the oil in the exhaust turbocharger will immediately stop circulating because the oil pump stops, but the rotor shaft of the turbocharger is still rotating at high speed under the action of inertia, which is easy to cause. The oil was cut off and its bearings burned to death. In addition, the exhaust manifold temperature of a diesel engine running under load is very high. If it stops suddenly, the heat will be transferred to the supercharger shell, and the engine oil that has stopped flowing will be tortured into coke. When the carbon deposit accumulates more and more, it will block the oil inlet and cause the bearing to be short of oil. Even if the oil inlet is not blocked, the carbon deposit will accelerate the wear of the bearing. For this reason, before stalling, the diesel engine must be gradually reduced in load, idling for an appropriate period of time, and then stalled after the turbocharger rotor shaft speed decreases and the oil temperature drops. After the flame is turned off, the turbocharger rotor shaft will continue to idle for a certain period of time, and a slight "humming" sound can sometimes be heard.
Exhaust gas turbochargers of different brands are widely used in various large and medium-sized diesel trucks,https://www.fcfuda.com/ flatbed trucks, dump trucks and various construction machinery. For example, the Shangchai 6135 diesel engine of the ZL-50 loader is equipped with GJ110 and J112 superchargers; the D6114 diesel engine of the PY-180 grader is equipped with a HIE supercharger; the Jiefang Engineering Wang dump truck is equipped with a WHIC supercharger; Steyr heavy-duty The car is equipped with Garrett superchargers and so on. They enable diesel engines to significantly increase power and torque under the condition of the same structural size, while reducing fuel consumption and exhaust pollution, especially in plateau areas. In the working process, the speed of the supercharger is as high as tens of thousands of revolutions per minute, and it runs under high exhaust temperature for a long time, so its working conditions are bad. In the use of the above-mentioned vehicles, the power drop and the increase in fuel consumption caused by the improper use of the turbocharger have occurred to varying degrees, which in turn led to a significant drop in operating efficiency and economic benefits. Based on the research on various failures of diesel exhaust turbochargers in engineering practice throughout the year, the author makes the following discussion on the causes of common failures and preventive measures.
1 Correct use of diesel engine
The first is the quality level of diesel oil. For low-supercharged diesel engines, diesel oil of no lower than CC grade should be used; for medium-supercharged diesel engines, diesel oil of no lower than CD grade should be used. The second is the viscosity grade of diesel engine oil. The appropriate viscosity grade should be selected according to the temperature conditions and the wear condition of the parts. The third is the cleanliness of diesel oil, because the rotor shaft of the exhaust turbocharger and its bearing (sleeve) are more precise. If the diesel oil is too dirty or deteriorated, impurities or abrasive particles will be brought into the turbocharger. It will accelerate the bearing wear, and if the lubricant film is not formed, the rotor shaft and the bearing will seize. Therefore, it is necessary to keep the oil clean, clean the oil filter frequently, and replace the damaged oil in time.
2 The correct way to start a cold car
After the vehicle is started, the diesel engine should be idle for a few minutes (depending on the engine temperature and the outside atmospheric temperature), the standby oil reaches a certain temperature and pressure, the flow performance is improved, and the turbocharger bearing is fully lubricated, the speed can be increased and the start Driving or putting into construction work, this is especially important when the outside temperature is low. For vehicles that have been parked for a long time (such as more than a few days), the turbocharger oil inlet pipe joint should be loosened before starting, and an appropriate amount of oil of the same brand as the oil pan should be added to the oil inlet to prevent poor lubrication during starting. The rotor shaft is ablated. Some users have experienced similar situations on the Jiefang Engineering Wang dump truck and on the Komatsu grader in Japan, and should be avoided as much as possible.
3 Correct flameout method
If a diesel engine is running at high speed, if it suddenly turns off, the oil in the exhaust turbocharger will immediately stop circulating because the oil pump stops, but the rotor shaft of the turbocharger is still rotating at high speed under the action of inertia, which is easy to cause. The oil was cut off and its bearings burned to death. In addition, the exhaust manifold temperature of a diesel engine running under load is very high. If it stops suddenly, the heat will be transferred to the supercharger shell, and the engine oil that has stopped flowing will be tortured into coke. When the carbon deposit accumulates more and more, it will block the oil inlet and cause the bearing to be short of oil. Even if the oil inlet is not blocked, the carbon deposit will accelerate the wear of the bearing. For this reason, before stalling, the diesel engine must be gradually reduced in load, idling for an appropriate period of time, and then stalled after the turbocharger rotor shaft speed decreases and the oil temperature drops. After the flame is turned off, the turbocharger rotor shaft will continue to idle for a certain period of time, and a slight "humming" sound can sometimes be heard.
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.
