Classification of Diesel Generator Governor
The load of the diesel
generator set is constantly changing, which requires that the output power of
the diesel engine also changes frequently, and the frequency of the power
supply is required to be stable, which requires the rotational speed of the diesel
engine to remain stable. Therefore, a speed governing mechanism must be
installed on the diesel engine of the diesel generator set. The governor
generally consists of two parts: the sensing element and the actuator.
According to the different working principle of the governor, it can be divided
into mechanical governor, electronic governor and electronic injection
governor.
Mechanical
governor
The mechanical speed
control system works by the flying hammer rotating at the corresponding speed
of the diesel engine. The centrifugal force generated by the flying hammer
during the rotation can automatically adjust the fuel inlet amount when the
generator set speed changes, thereby achieving the purpose of automatically
adjusting the unit speed.
Schematic diagram of the
centrifugal full speed governor
1. Governor shaft
2. Flying hammer support
3. Flying hammer pin
4. Flying hammer
5. Slide bushing
6. Pendulum bar/swing
rod
7. Swing link pin
8. Governor spring
9. Fuel injection pump
rack
10. Operating handle
11. Sector rack
12. Maximum position
speed limit screw
13. Minimum position
speed limit screw
Move the position of the
operating handle to change the tension of the spring, so that the tension and
thrust on the swing rod are in a new equilibrium position. At the same time,
the position of the fuel pump rack is changed to adjust the diesel engine to
the required speed and work automatically and stably at this speed.
Under normal
circumstances, the speed of the diesel generator set with mechanical speed regulation
system will decrease slightly with the increase of the load, and the automatic
variation range of the speed is ±5%. When the unit has a rated load, the unit's
rated speed is approximately 1500 rpm.
Electronic
governor
The electronic governor
is a controller that controls the speed of the engine. Its main functions are:
to keep the engine idle speed at a set speed; keep the engine's operating speed
at a preset speed without being affected by load changes. The electronic
governor is mainly composed of three parts: controller, speed sensor and
actuator.
The engine speed sensor
is a variable reluctance electromagnet that is mounted above the flywheel gear
ring in the flywheel housing. When the gears on the ring gear pass under the
electromagnet, an alternating current is induced (one gear produces a cycle).
The electronic
controller compares the input signal with the preset value, and then sends the
correction signal or the maintenance signal to the actuator; the controller can
perform various adjustments to adjust the idle speed, running speed,
sensitivity and stability of the controller. starting fuel quantity and engine
speed acceleration;
The actuator is an
electromagnet that converts the control signals from the controller into
control forces. The control signal transmitted by the controller to the
actuator is transmitted to the fuel control rack of the fuel injection pump
through a connecting rod system.
Electronic
injection speed governor
The EFI (Electronic fuel
injection) gen set controls the injector operation by adjusting various
information of the diesel engine detected by a series of sensors installed on
the engine through an electronic control module (ECU) on the diesel engine,
adjusting the injection timing and fuel injection quantity to make the diesel
engine in the best working condition.
The main advantages of
EFI speed regulation: Through the electronic control of injector injection
timing, fuel injection quantity and high pressure injection pressure, the
mechanical performance of the diesel engine can be optimized; the fuel
injection quantity can be precisely controlled by ECU; the fuel consumption of
the diesel engine decreases in normal operation, which is more economical and
lower in emissions, and conforms to EURO non-highway internal combustion engine
emission standards;
Through the data
communication line, it can be connected with an external instrument panel and a
special diagnostic tool, which makes installation easier, increases the
detection point of the fault point, and is more convenient for troubleshooting.
The composition of the EFI diesel engine management system is shown in Figure
2.4:
Description: CIU refers
to the control interface device, such as the control panel; ECU refers to the
electronic control module, which is installed on the diesel engine.
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