A diesel generator starting control circuit

Abstract

The present invention relates to the field of generators, and in particular to a diesel generator starting control circuit, comprising a relay KA1, a rectifier filter circuit, a voltage divider circuit, a coupler U1 and a transistor Q1; the normally closed contacts of the relay KA1 are electrically connected to the electric door lock switch and the starter motor end respectively, the input end of the rectifier filter circuit is electrically connected to the generator flywheel winding, and the starter motor end is used to start the engine to make the generator flywheel winding output AC power; the generator flywheel winding is electrically connected to the input end of the coupler U1 after passing through the rectifier filter circuit and the voltage divider circuit that are electrically connected in sequence, and the output end of the coupler U1 is electrically connected to the relay KA1 through the transistor Q1. Through the coordination relationship between the electronic components, the starter motor can be shut down after starting the engine, thereby effectively protecting the starter motor.

Description

[0001] This case is a divisional application of the patent application with application number 202010914977.X, application date 2020-09-03, and title “A diesel generator starting control circuit that effectively protects the starting motor” as the parent case. Technical Field

[0002] The invention relates to the field of generators, and in particular to a diesel generator starting control circuit which can effectively protect a starting motor. Background Art

[0003] Diesel generators are widely used due to their fuel efficiency and high power. The engine is started by a starter motor. However, after the engine has started successfully, the starter motor is still running, which can easily cause the two gears to clash and cause gear wear. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a diesel generator starting control circuit which can effectively protect the starting motor.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A diesel generator starting control circuit for effectively protecting a starting motor comprises a relay KA1, a rectifier filter circuit, a voltage divider circuit, a coupler U1 and a transistor Q1;

[0007] The normally closed contact of the relay KA1 is electrically connected to the electric door lock switch and the starter motor end respectively, the input end of the rectifier filter circuit is electrically connected to the generator flywheel winding, and the starter motor end is used to start the engine to make the generator flywheel winding output AC power;

[0008] The generator flywheel winding is electrically connected to the input end of the coupler U1 through a rectifier filter circuit and a voltage divider circuit which are electrically connected in sequence. The output end of the coupler U1 is electrically connected to the relay KA1 through a transistor Q1 and further includes a diode D1. The diode D1 is connected in parallel with the relay KA1.

[0009] It also includes a diode D3, a resistor R8, a transistor Q2 and a relay KA2; the positive electrode of the diode D3 is electrically connected to the normally closed contact of the relay KA1, the negative electrode of the diode D3 is electrically connected to one end of the resistor R8, the other end of the resistor R8 is electrically connected to the base of the transistor Q2, the collector of the transistor Q2 is electrically connected to the fuel valve through the relay KA2, and the emitter of the transistor Q2 is grounded.

[0010] The beneficial effects of the present invention are:

[0011] The present invention provides a diesel generator starting control circuit for effectively protecting the starter motor, including a relay KA1, a rectifier filter circuit, a voltage divider circuit, a coupler U1 and a transistor Q1. Through the coordination relationship between the electronic components, the starter motor can be shut down after starting the engine, thereby effectively protecting the starter motor. The diode D1 is used to discharge the reverse electromotive force of the relay KA1 coil to protect the transistor Q1 from damage. In the process of starting the motor, the positive voltage of the battery provides a trigger voltage to the base of the transistor Q2 through the diode D3 and the resistor R8. When the transistor Q2 is saturated and turned on, the relay KA2 coil connected in series with the transistor Q2 is energized and attracted, and the standby voltage at the common end of the relay KA2 provides a working voltage to the fuel valve end L1 through the normally open contact of the relay KA2. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The present invention is a circuit connection diagram of a diesel generator starting control circuit that effectively protects the starting motor. DETAILED DESCRIPTION

[0013] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0014] Please refer to Figure 1 , a diesel generator starting control circuit for effectively protecting a starting motor provided by the present invention comprises a relay KA1, a rectifier filter circuit, a voltage divider circuit, a coupler U1 and a transistor Q1;

[0015] The normally closed contact of the relay KA1 is electrically connected to the electric door lock switch and the starter motor end respectively, the input end of the rectifier filter circuit is electrically connected to the generator flywheel winding, and the starter motor end is used to start the engine to make the generator flywheel winding output AC power;

[0016] The generator flywheel winding is electrically connected to the input end of the coupler U1 through a rectifier filter circuit and a voltage divider circuit which are electrically connected in sequence. The output end of the coupler U1 is electrically connected to the relay KA1 through a transistor Q1 and further includes a diode D1. The diode D1 is connected in parallel with the relay KA1.

[0017] It also includes a diode D3, a resistor R8, a transistor Q2 and a relay KA2; the positive electrode of the diode D3 is electrically connected to the normally closed contact of the relay KA1, the negative electrode of the diode D3 is electrically connected to one end of the resistor R8, the other end of the resistor R8 is electrically connected to the base of the transistor Q2, the collector of the transistor Q2 is electrically connected to the fuel valve through the relay KA2, and the emitter of the transistor Q2 is grounded.

[0018] From the above description, it can be seen that the beneficial effects of the present invention are: the present invention provides a diesel generator starting control circuit that effectively protects the starter motor, including a relay KA1, a rectifier filter circuit, a voltage divider circuit, a coupler U1 and a transistor Q1. Through the coordination relationship between the electronic components, the starter motor can be shut down after starting the engine, thereby effectively protecting the starter motor. The diode D1 is used to discharge the reverse electromotive force of the relay KA1 coil to protect the transistor Q1 from damage. In the process of starting the motor, the positive voltage of the battery provides a trigger voltage to the base of the transistor Q2 through the diode D3 and the resistor R8. When the transistor Q2 is saturated and turned on, the relay KA2 coil connected in series with the transistor Q2 is energized and attracted, and the standby voltage at the common end of the relay KA2 provides a working voltage to the fuel valve end L1 through the normally open contact of the relay KA2.

[0019] Furthermore, it also includes a resistor R5, a resistor R6 and a capacitor C3; the third pin of the coupler U1 is electrically connected to one end of the resistor R5, and the other end of the resistor R5 is electrically connected to one end of the capacitor C3, the resistor R6 and the base of the transistor Q1 respectively; the other end of the capacitor C3, the other end of the resistor R6 and the emitter of the transistor Q1 are all grounded.

[0020] Furthermore, the rectification and filtering circuit includes a rectifier BD and a capacitor C1; an AC input end of the rectifier BD is electrically connected to a flywheel winding of a generator, and an output end of the rectifier BD is connected in parallel to the capacitor C1.

[0021] It can be seen from the above description that, through the above specific circuit structure, the alternating current output by the flywheel winding of the generator is rectified and filtered to obtain direct current.

[0022] Furthermore, the voltage divider circuit includes a resistor R1 and a resistor R2; one end of the resistor R1 is electrically connected to one end of the capacitor C1, the other end of the resistor R1 is electrically connected to one end of the resistor R2, and the other end of the resistor R2 is electrically connected to the other end of the capacitor C1.

[0023] It can be seen from the above description that the voltage division function is achieved through the above specific circuit structure.

[0024] Furthermore, it also includes a capacitor C2 and a voltage regulator VD; one end of the capacitor C2 is electrically connected to one end of the resistor R2 and the negative electrode of the voltage regulator VD respectively, the positive electrode of the voltage regulator VD is electrically connected to the first pin of the coupler U1, and the other end of the capacitor C2 is electrically connected to the other end of the resistor R2 and the second pin of the coupler U1 respectively.

[0025] It can be seen from the above description that the filtering and voltage stabilization functions are achieved through the above specific circuit structure.

[0026] Furthermore, it also includes a diode D4 and a resistor R7; the cathode of the diode D4 is electrically connected to the cathode of the diode D3, the anode of the diode D4 is electrically connected to one end of the resistor R7, the anode of the diode D4 is grounded, the other end of the resistor R7 is electrically connected to the relay KA2 and the fuel valve respectively, and one end of the resistor R7 is electrically connected to the low-voltage contact of the engine oil.

[0027] From the above description, it can be known that the standby voltage at the common end of relay KA2 continues to provide trigger voltage to the base of transistor Q2 through the normally open contact of relay KA2 and resistor R7, diode D4 and resistor R8. This is mainly to ensure that when the electric door lock switch rotates out of the START state, this voltage can continue to supply power to form a self-locking circuit, transistor Q2 continues to be saturated and turned on, and relay KA2 continues to be attracted and work.

[0028] Furthermore, it also includes a diode D2 and a capacitor C4; the anode of the diode D2 is electrically connected to the normally closed contact of the relay KA1, the cathode of the diode D2 is electrically connected to one end of the capacitor C4 and the anode of the diode D3 respectively, and the other end of the capacitor C4 is grounded.

[0029] From the above description, it can be seen that during the process of starting the motor, the positive voltage of the battery charges the capacitor C4 through the diode D2, and the low-voltage contact LOP of the oil is connected to the ground (GND) when the engine fails to start successfully but the oil pressure comes up, that is, when there is a lack of oil. In other words, the low-voltage contact LOP of the oil is connected to the ground (GND), indicating that the engine cannot be started successfully. In order to achieve the smooth start of the engine when the low-voltage contact LOP of the oil is connected to the ground (GND), the capacitor C4 plays a role of delayed power supply. When the transistor Q2 is saturated and turned on, the positive voltage at the common end of the relay KA2 continues to provide a trigger voltage to the base of the transistor Q2 through the resistor R7, the diode D4, and the resistor R8, forming a self-locking circuit. When the oil low-voltage contact LOP is connected to the ground (GND), the voltage of the resistor R7 and the diode D4 is pulled down. At this time, the capacitor C4 discharges to provide a saturation voltage to the resistor R8 and the base of the transistor Q2. The relay KA2 continues to remain energized, and the positive voltage at the common end of the relay KA2 continues to provide voltage to the fuel valve L1 end. The fuel valve works normally, which helps to start the engine smoothly.

[0030] Furthermore, it also includes a diode D5; the diode D5 is connected in parallel with the relay KA2.

[0031] From the above description, it can be seen that the diode D5 is used to discharge the reverse electromotive force of the relay KA2 coil to protect the transistor Q2 from being damaged.

[0032] Please refer to Figure 1 , Embodiment 1 of the present invention is:

[0033] The present invention provides a diesel generator starting control circuit for effectively protecting a starting motor, comprising a relay KA1, a rectifier filter circuit, a voltage divider circuit, a coupler U1 and a transistor Q1;

[0034] The normally closed contact of the relay KA1 is electrically connected to the electric door lock switch and the starter motor end respectively, the input end of the rectifier filter circuit is electrically connected to the generator flywheel winding, and the starter motor end is used to start the engine to make the generator flywheel winding output AC power;

[0035] The generator flywheel winding is electrically connected to the input end of the coupler U1 through a rectifier filter circuit and a voltage divider circuit which are electrically connected in sequence, and the output end of the coupler U1 is electrically connected to the relay KA1 through a transistor Q1.

[0036] exist Figure 1 In the diagram, the starter motor end is represented by QD, the electric door lock switch is represented by ON, the starter motor switch is represented by START, the oil low-voltage contact is represented by LOP, and the fuel valve is represented by L1.

[0037] The diesel generator start-up control circuit also includes a resistor R5, a resistor R6 and a capacitor C3; the third pin of the coupler U1 is electrically connected to one end of the resistor R5, and the other end of the resistor R5 is electrically connected to one end of the capacitor C3, the resistor R6 and the base of the transistor Q1 respectively; the other end of the capacitor C3, the other end of the resistor R6 and the emitter of the transistor Q1 are all grounded. In this embodiment, the resistance value of the resistor R5 is 1KΩ, the resistance value of the resistor R6 is 10KΩ, the specification of the capacitor C3 is 4.7μF / 50V, and the model of the transistor Q1 is MMBT5551. The model of the coupler U1 is PC817.

[0038] In this embodiment, the rectifier and filter circuit includes a rectifier BD and a capacitor C1; the AC input end of the rectifier BD is electrically connected to the generator flywheel winding, and the output end of the rectifier BD is connected in parallel with the capacitor C1. Through the above specific circuit structure, the AC power output by the generator flywheel winding is rectified and filtered to obtain DC power. In this embodiment, the specification of the capacitor C1 is 100μF / 50V.

[0039] The voltage divider circuit includes a resistor R1 and a resistor R2; one end of the resistor R1 is electrically connected to one end of the capacitor C1, the other end of the resistor R1 is electrically connected to one end of the resistor R2, and the other end of the resistor R2 is electrically connected to the other end of the capacitor C1. The voltage divider function is realized through the above-mentioned specific circuit structure. In this embodiment, the resistance value of the resistor R1 is 4.3KΩ, and the resistance value of the resistor R2 is 7.5KΩ. In this solution, a resistor R3 is also included, one end of the resistor R3 is electrically connected to the other end of the resistor R1, and the other end of the resistor R3 is electrically connected to the other end of the resistor R2.

[0040] The diesel generator start-up control circuit also includes a capacitor C2 and a voltage regulator tube VD; one end of the capacitor C2 is electrically connected to one end of the resistor R2 and the negative electrode of the voltage regulator tube VD, the positive electrode of the voltage regulator tube VD is electrically connected to the first pin of the coupler U1, and the other end of the capacitor C2 is electrically connected to the other end of the resistor R2 and the second pin of the coupler U1. The filtering and voltage stabilization functions are realized through the above-mentioned specific circuit structure. In this embodiment, the specification of the capacitor C2 is 4.7μF / 50V. The specification of the voltage regulator tube VD is 5V1.

[0041] The diesel generator start-up control circuit further includes a diode D1; the diode D1 is connected in parallel with the relay KA1. The diode D1 is used to discharge the reverse electromotive force of the relay KA1 coil to protect the transistor Q1 from damage. In this embodiment, the model of the diode D1 is 1N4007. The diesel generator start-up control circuit further includes a resistor R4, one end of the resistor R4 is electrically connected to the fourth pin of the coupler U1, and the other end of the resistor R4 is electrically connected to the cathode of the diode D1. The resistance value of the resistor R4 is 4.7KΩ.

[0042] The diesel generator start-up control circuit also includes a diode D3, a resistor R8, a transistor Q2 and a relay KA2; the positive electrode of the diode D3 is electrically connected to the normally closed contact of the relay KA1, the negative electrode of the diode D3 is electrically connected to one end of the resistor R8, the other end of the resistor R8 is electrically connected to the base of the transistor Q2, the collector of the transistor Q2 is electrically connected to the fuel valve through the relay KA2, and the emitter of the transistor Q2 is grounded. In the process of starting the motor, the positive voltage of the battery provides a trigger voltage to the base of the transistor Q2 through the diode D3 and the resistor R8. When the transistor Q2 is saturated and turned on, the coil of the relay KA2 connected in series to the transistor Q2 is energized and attracted, and the standby voltage of the common end of the relay KA2 provides a working voltage to the fuel valve end L1 through the normally open contact of the relay KA2. In this embodiment, the model of the diode D3 is 1N4007, the resistance of the resistor R8 is 3.9KΩ, and the model of the transistor Q2 is MMBT5551.

[0043] The above diesel generator start-up control circuit also includes a diode D4 and a resistor R7; the cathode of the diode D4 is electrically connected to the cathode of the diode D3, the anode of the diode D4 is electrically connected to one end of the resistor R7, the anode of the diode D4 is grounded, the other end of the resistor R7 is electrically connected to the relay KA2 and the fuel valve respectively, and one end of the resistor R7 is electrically connected to the low-voltage contact of the engine oil. The standby voltage at the common end of the relay KA2 continues to provide a trigger voltage to the base of the transistor Q2 through the normally open contact of the relay KA2 and the resistor R7, the diode D4, and the resistor R8. It is mainly to ensure that when the electric door lock switch rotates out of the START start state, this voltage can continue to supply power to form a self-locking loop, the transistor Q2 continues to be saturated and turned on, and the relay KA2 continues to work. In this embodiment, the model of the diode D4 is 1N4007, and the resistance value of the resistor R7 is 2KΩ.

[0044] The above diesel generator start-up control circuit also includes a diode D2 and a capacitor C4; the positive electrode of the diode D2 is electrically connected to the normally closed contact of the relay KA1, the negative electrode of the diode D2 is electrically connected to one end of the capacitor C4 and the positive electrode of the diode D3 respectively, and the other end of the capacitor C4 is grounded. In the process of starting the motor, the positive voltage of the battery charges the capacitor C4 through the diode D2, and the low-voltage contact LOP of the oil is connected to the ground (GND) when the engine fails to start successfully but the oil pressure comes up, that is, when there is a lack of oil. In other words, the low-voltage contact LOP of the oil is connected to the ground (GND), indicating that the engine cannot be started successfully. In order to achieve the smooth start of the engine when the low-voltage contact LOP of the oil is connected to the ground (GND), the capacitor C4 plays a role of delayed power supply. When the transistor Q2 is saturated and turned on, the positive voltage of the common end of the relay KA2 continues to provide a trigger voltage to the base of the transistor Q2 through the resistor R7, the diode D4, and the resistor R8, forming a self-locking loop. When the oil low voltage contact LOP is connected to the ground (GND), the voltage of the resistor R7 and the diode D4 is pulled down. At this time, the capacitor C4 discharges to provide a saturation voltage to the resistor R8 and the base of the transistor Q2, and the relay KA2 continues to be attracted. The positive voltage of the common terminal of the relay KA2 continues to provide a voltage to the fuel valve L1 terminal, and the fuel valve works normally, which plays a role in starting the engine smoothly. In this embodiment, the model of the diode D2 is 1N4007, and the specification of the capacitor C4 is 470μF / 35V.

[0045] The diesel generator start-up control circuit further includes a diode D5; the diode D5 is connected in parallel with the relay KA2. The diode D5 is used to discharge the reverse electromotive force of the relay KA2 coil to protect the transistor Q2 from damage. In this embodiment, the model of the diode D5 is 1N4007.

[0046] The working principle of the above diesel generator starting control circuit is:

[0047] 1. When the electric door lock switch rotates to the (ON) state, the positive voltage of the battery provides power to the coils of relays KA1 and KA2, the common end of relay KA2 and one end of resistor R4, and enters the standby state.

[0048] 2. When the electric door lock switch rotates to the (START) starting state, the positive voltage of the battery provides working voltage to the starter motor through the normally closed contact of relay KA1, and the starter motor successfully starts the engine.

[0049] When the engine is running, the flywheel winding of the generator outputs AC power which enters the AC1 and AC2 ports. After being rectified by the rectifier block BD and filtered by the capacitor C1, DC power is obtained. The positive voltage is divided by the resistors R1 and R2, filtered by the capacitor C2, and stabilized by the voltage regulator tube VD. A voltage signal is provided to the pins 11 and 2 of the coupler U1, making the pins 3 and 4 of the coupler U1 turned on.

[0050] In standby mode, the positive voltage provides a trigger voltage to the base of transistor Q1 through resistor R5, resistor R6 and capacitor C3. When transistor Q1 is saturated and turned on, the coil of relay KA1 connected in series with transistor Q1 is energized, relay KA1 is energized and the normally closed point is disconnected. There is no voltage output at the QD end of the relay, and the starter motor stops, thereby protecting the starter motor.

[0051] 3. During the process of starting the motor, the positive voltage of the battery charges the capacitor C4 through the diode D2, and the other path provides a trigger voltage to the base of the transistor Q2 through the diode D3 and the resistor R8. When the transistor Q2 is saturated and turned on, the coil of the relay KA2 connected in series with the transistor Q2 is energized and attracted, and the standby voltage at the common end of the relay KA2 provides the working voltage to the fuel valve end L1 through the normally open contact of the relay KA2. At the same time, one path continues to provide a trigger voltage to the base of the transistor Q2 through the resistor R7, the diode D4, and the resistor R8 (when the electric door lock switch rotates to exit the (START) starting state, this voltage continues to supply power to form a self-locking circuit, the transistor Q2 continues to be saturated and turned on, and the relay KA2 continues to be attracted and work).

[0052] 4. When the engine fails to start but the oil pressure rises, that is, when there is a lack of engine oil, LOP is connected to the ground (GND).

[0053] 5. To avoid the engine not being started smoothly when the LOP low oil pressure input terminal is connected to the ground (GND), capacitor C4 plays a role of delayed power supply. When the transistor Q2 is saturated and turned on, the positive voltage at the common terminal of relay KA2 continues to provide trigger voltage to the base of transistor Q2 through resistor R7, diode D4, and resistor R8, forming a self-locking loop. When LOP is connected to the ground (GND), the voltage of resistor R7 and diode D4 is pulled down. At this time, capacitor C4 discharges to provide saturation voltage to resistor R8 and the base of transistor Q2, and relay KA2 continues to stay energized. The positive voltage at the common terminal of relay KA2 continues to provide voltage to the fuel valve L1, and the fuel valve works normally, which plays a role in starting the engine smoothly.

[0054] 6. The diode D1 in the circuit discharges the reverse electromotive force of the relay KA1 coil to protect the transistor Q1 from damage. The diode D2 prevents the capacitor C4 from discharging to the starter motor end. The diode D3 is used to prevent the voltage in the self-locking circuit from discharging to the capacitor C4 and the starter motor end. The diode D4 is used to prevent the positive voltage from being sent to the LOP low oil pressure input end during the starter motor process, thereby damaging the LOP low oil pressure sensor. The diode D5 discharges the reverse electromotive force of the relay KA2 coil to protect the transistor Q2 from damage.

[0055] In summary, the present invention provides a diesel generator starting control circuit that effectively protects the starter motor, including a relay KA1, a rectifier filter circuit, a voltage divider circuit, a coupler U1 and a transistor Q1. Through the coordination relationship between the electronic components, the starter motor can be shut down after starting the engine, thereby effectively protecting the starter motor. The diode D1 is used to discharge the reverse electromotive force of the relay KA1 coil to protect the transistor Q1 from damage. In the process of starting the motor, the positive voltage of the battery provides a trigger voltage to the base of the transistor Q2 through the diode D3 and the resistor R8. When the transistor Q2 is saturated and turned on, the relay KA2 coil connected in series with the transistor Q2 is energized and attracted, and the standby voltage at the common end of the relay KA2 provides a working voltage to the fuel valve end L1 through the normally open contact of the relay KA2.

[0056] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A diesel generator starting control circuit, characterized in that: It includes relay KA1, coupler U1, transistor Q1, diode D1, diode D3, resistor R8, transistor Q2 and relay KA2; The normally closed contacts of the relay KA1 are electrically connected to the electric door lock switch and the starter motor end respectively, and the starter motor end is used to start the engine to make the generator flywheel winding output AC power; The generator flywheel winding is electrically connected to the input end of the coupler U1, and the output end of the coupler U1 is electrically connected to the relay KA1 through the transistor Q1; The diode D1 is connected in parallel with the relay KA1; the anode of the diode D1 is electrically connected to the collector of the transistor Q1, the cathode of the diode D1 is electrically connected to the electric door lock switch, and the diode D1 is used to discharge the reverse electromotive force of the relay KA1 coil; The anode of the diode D3 is electrically connected to the normally closed contact of the relay KA1, the cathode of the diode D3 is electrically connected to one end of the resistor R8, the other end of the resistor R8 is electrically connected to the base of the transistor Q2, and the collector of the transistor Q2 is electrically connected to the fuel valve through the relay KA2; during the process of starting the motor, the positive voltage of the battery provides a trigger voltage to the base of the transistor Q2 through the diode D3 and the resistor R8, when the transistor Q2 is saturated and turned on, the coil of the relay KA2 connected in series to the transistor Q2 is energized and attracted, and the standby voltage at the common end of the relay KA2 provides a working voltage to the fuel valve end L1 through the normally open contact of the relay KA2; It also includes a resistor R5, a resistor R6 and a capacitor C3; the third pin of the coupler U1 is electrically connected to one end of the resistor R5, and the other end of the resistor R5 is electrically connected to one end of the capacitor C3, the resistor R6 and the base of the transistor Q1 respectively; the other end of the capacitor C3, the other end of the resistor R6 and the emitter of the transistor Q1 are all grounded; the emitter of the transistor Q2 is grounded.

2. The diesel generator starting control circuit according to claim 1, characterized in that: It also includes a diode D4 and a resistor R7; the cathode of the diode D4 is electrically connected to the cathode of the diode D3, the anode of the diode D4 is electrically connected to one end of the resistor R7, the anode of the diode D4 is grounded, the other end of the resistor R7 is electrically connected to the relay KA2 and the fuel valve respectively, and one end of the resistor R7 is electrically connected to the low-voltage contact of the engine oil.

3. The diesel generator starting control circuit according to claim 1, characterized in that: It also includes a diode D2 and a capacitor C4; the anode of the diode D2 is electrically connected to the normally closed contact of the relay KA1, the cathode of the diode D2 is electrically connected to one end of the capacitor C4 and the anode of the diode D3 respectively, and the other end of the capacitor C4 is grounded.

4. The diesel generator starting control circuit according to claim 1, characterized in that: It also includes a diode D5; the diode D5 is connected in parallel with the relay KA2; the anode of the diode D5 is electrically connected to the collector of the transistor Q2, and the cathode of the diode D5 is electrically connected to the electric door lock switch.

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