Diesel Generator Governors: Mechanical vs. Electronic Types
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The governor of a diesel generator set is a crucial device to ensure the stability of the engine's speed. Based on their working principles and construction, governors can be divided into mechanical and electronic types. This article will provide a detailed introduction to the working principles and applications of these two types of diesel generator governors, and discuss the differences between electronic fuel injection and electronic control technologies within electronic governors.
Mechanical Governor
The mechanical governor is an important device used to control and stabilize the speed of a diesel engine in various mechanical equipment. It is divided into horizontal and vertical types according to its installation method. The following will introduce the working principle and application of the mechanical governor.
1. Working Principle
The mechanical governor comes in two types, horizontal and vertical, mainly composed of a governor weight, flyweights, speed control springs, adjustment screws, and transmission rods. The working principle is based on the balance between the centrifugal force of the flyweights and the tension of the speed control springs. When the speed reaches the rated value, these two forces are balanced; when the speed is higher than the rated value, the centrifugal force of the flyweights increases, surpassing the tension of the springs, causing the flyweights to open and pull the rod to reduce the throttle, allowing the diesel engine to automatically return to the rated speed. Conversely, when the speed is lower than the rated value, the flyweights come closer together, pulling the rod to increase the throttle and speed up the diesel engine.
2. Application Pros and Cons
Due to its simple structure, low cost, and ease of maintenance, the mechanical governor is widely used in diesel engines where the speed control accuracy is not highly demanded. Specific applications include agricultural machinery, small generator sets, and some industrial equipment. However, because its speed control relies on the physical movement of mechanical parts, it has lower accuracy and slower response speed, which shows certain limitations in applications requiring high-speed control accuracy and rapid response.
Electronic Governor
The electronic governor is a widely used automatic speed control component in diesel generator sets, with its core function being to maintain a constant engine speed unaffected by load changes. The electronic governor mainly consists of a speed-setting potentiometer, a speed sensor, a controller, an actuator, and a controllable silicon voltage regulator circuit. The following will introduce the working principle, application, and differences in electronic injection governor and electronic governor.
1. Working Principle
The electronic governor ensures a constant engine speed by controlling the generator's speed under various working conditions. The workflow is as follows.
Speed setting: The required engine speed is set through the speed-setting potentiometer.
Speed measurement: The speed sensor measures the actual engine speed through the gear ring on the flywheel and transmits the measured value to the controller.
Comparison and adjustment: The controller compares the actual speed value with the set value, calculates the difference, and amplifies and processes the signal through the control circuit.
Execution: The amplified signal drives the actuator to adjust the fuel pump rack's fuel supply, thereby regulating the engine speed to maintain it at the set value. The electronic governor can also select the degree of unevenness according to specific needs for differential-free speed control to eliminate speed deviations caused by load changes. Its various accessory devices can achieve functions such as automatic synchronization, load distribution, and load presetting.
2. Application Pros and Cons
The electronic governor has the advantages of high speed control accuracy, fast response speed, and powerful functions, and is widely used in modern diesel generator sets, industrial equipment, and automotive engines. Its disadvantages include a complex structure, high cost, and the need for regular maintenance and calibration.
3. Electronic Governor and Electronic Injection Governor
The electronic governor includes two methods: electronic governor and electronic injection governor, which differ in the fuel supply system and control method.
Electronic Governor
The electronic governor uses a speed sensor to feedback the speed signal, the governor compares the speed signal with the preset speed value, and drives the actuator to control the fuel supply rack or slider to achieve speed control. Its fuel supply signal depends solely on the speed signal, and the fuel quantity adjustment is achieved by the mechanical action of the actuator.
Electronic Injection Governor
The electronic injection governor uses multiple sensors (such as speed, injection time, intake air temperature, intake pressure, fuel temperature, coolant temperature, etc.) to transmit signals, input real-time detected data into the computer (ECU), compare with the set parameter values, calculate the target value, and then transmit it to the actuator. The high-pressure fuel pump of the EFI machine generates high-pressure fuel in the high-pressure fuel chamber of the injector and controls the injection through the solenoid valve.
Main Differences
Fuel supply system: The injection pressure of the electronic governor's fuel supply system is related to the engine speed and load, while the electronic injection governor 's fuel supply system does not depend on the injection pressure control of speed and load.
Injection timing: The injection timing of the electronic governor depends on the rotation angle of the camshaft and is fixed after adjustment; the injection timing of the electronic injection governor is controlled by the electronic control system, independent of machine rotation, capable of rapid fuel cut-off, reducing black smoke emissions and exhaust.
Injection pressure: The injection pressure of the electronic injection governor machine has been increased from 100MPa to 180MPa, improving the mixing quality of diesel and air, shortening the ignition delay time, and reducing the amount of exhaust emissions.
Mechanical and electronic governors each have their strengths and weaknesses. Mechanical governors have a simple structure and are easy to maintain but have lower speed control accuracy. Electronic governors have high speed control accuracy and powerful functions, suitable for modern diesel generator sets. The two electronic governor technologies of electronic injection governor and electronic injection governor differ in the fuel supply system and injection pressure control, with electronic injection governor technology more suitable for applications requiring high efficiency and low emissions. By comparison, the appropriate type of governor can be selected according to specific application needs to achieve optimal performance and efficiency.
