Diesel generating set oil pressure alarm circuit

Abstract

The application relates to a diesel generator set oil pressure alarm circuit which comprises a power supply, a starting module, an alarm cut-off module and an oil pressure alarm protection module; the starting module comprises a starting switch, a starting button and a lazy-full speed switch; the alarm cut-off module comprises a first relay; the oil pressure alarm protection module comprises an oil pressure sensor, a second relay, a third relay, a fourth relay KA4 and an alarm indicator TP. Through the first relay, the diesel generator set oil pressure alarm circuit can not only normally monitor whether the set is in a low oil pressure state during the starting process to provide necessary low oil pressure fault signals for an operator, but also can avoid the protection action caused by the low oil pressure fault during the starting process, so that the set can be normally started.

Description

Technical Field

[0001] This application relates to the field of alarm protection technology for diesel generator sets, specifically to an oil pressure alarm circuit for diesel generator sets. Background Technology

[0002] The typical startup process of a diesel generator set is as follows: The generator set receives a start signal, and the starter valve simultaneously idles. After the oil pressure is raised to normal operating conditions via the valve, the generator set receives a full-speed signal and enters full-speed operation. In automatic start mode, both the start signal and the full-speed signal are sent automatically by the controller; in manual start mode, both signals are sent manually by the operator using the corresponding switches. Oil pressure monitoring is required during operation. If the oil pressure falls below the normal value, a shutdown operation must be performed to protect the diesel generator set. Common oil pressure alarm protection circuits use an oil pressure sensor to send a low oil pressure signal, activating the corresponding alarm or protection relay, thus triggering the alarm or executing a shutdown protection action. However, during the startup phase of a diesel engine set, a low oil pressure period is inevitable. In this case, the commonly used oil pressure alarm protection circuit's shutdown protection action would prevent the generator set from starting normally.

[0003] Patent document CN208486923U discloses a circuit to avoid low oil pressure alarms during generator set startup. It takes advantage of the characteristic that low oil pressure only occurs during the idling stage of diesel generator set startup. It uses a full-speed signal to control the oil pressure alarm protection circuit to connect to the power supply. That is, the oil pressure alarm protection circuit will only be connected to the power supply and perform the oil pressure alarm protection function when the generator set is at full speed. However, after the generator set performs the oil pressure alarm protection action, the alarm signal will disappear regardless of whether the low oil pressure fault is eliminated. This makes it inconvenient for operators to troubleshoot the cause of the fault and perform fault repair.

[0004] In response, patent document CN112727598B discloses a highly reliable diesel generator set oil pressure alarm circuit, which adds an alarm sustaining relay to the patent document CN208486923U, thus overcoming the defect that the alarm signal disappears immediately after the unit performs the oil pressure alarm protection action. However, in manual start mode, because the oil pressure alarm protection circuit is not powered on during the idling stage, the operator lacks an indication of a low oil pressure alarm signal and cannot accurately determine whether the unit can enter full-speed operation at the current moment. They can only rely on experience to manually send a start signal, wait for the unit to idle for a period of time, and then manually send a full-speed signal. However, if the current oil pressure of the unit does not meet the oil pressure requirements of the full-speed operation state or the unit does have a low oil pressure fault, it will damage the diesel generator set, shorten the service life of the unit, or cause start failure, but the lack of fault signal indication increases the time and difficulty for the operator to troubleshoot. Summary of the Invention

[0005] The purpose of this invention is to provide a diesel generator set oil pressure alarm circuit that can monitor whether the generator set is in a low oil pressure state during the startup process, provide the operator with the necessary low oil pressure fault signal, and prevent the protection action caused by the low oil pressure fault during the startup process, so as to ensure that the generator set can start normally.

[0006] The technical solution adopted in this invention is: a diesel generator set oil pressure alarm circuit, characterized in that it includes a power supply BAT, a starting module, an alarm cut-off module, and an oil pressure alarm protection module;

[0007] The starting module includes a start switch SA1, a start button SB1, and an idle-full speed switch SA2. The start switch SA1 is provided with a first power supply branch and a second power supply branch. One end of the first power supply branch and the second power supply branch are connected to the positive terminal of the power supply BAT, and the other end of the second power supply branch is connected to the start button SB1. The start switch SA1 has three states: stop, start, and run. In the stop state, neither the first power supply branch nor the second power supply branch is connected to the power supply BAT. In the run state, the first power supply branch is connected to the power supply BAT, and the second power supply branch is not connected to the power supply BAT. In the start state, both the first power supply branch and the second power supply branch are connected to the power supply BAT.

[0008] The alarm cut-off module includes a first relay KA1. One end of the coil of the first relay KA1 is connected to the start button SB1, and the other end is connected to the negative terminal of the power supply BAT. One end of the normally open contact KA1-O of the first relay is connected to the other end of the first power supply branch, and the other end is connected to the idle-full speed switch SA2.

[0009] The oil pressure alarm protection module includes an oil pressure sensor YY, a second relay KA2, a third relay KA3, and an alarm indicator TP. One end of the oil pressure sensor YY is connected to the coil of the second relay KA2, and the other end is connected to the negative terminal of the power supply BAT. The other end of the coil of the second relay KA2 is connected to the positive terminal of BAT. One end of the normally open contact KA2-O of the second relay is connected to the positive terminal of BAT, and the other end is connected to the coil of the third relay KA3. The coil of the third relay KA3 is also connected to the negative terminal of the power supply BAT. The normally closed contact KA3-C of the third relay is connected in parallel with the normally open contact KA1-O of the first relay. The alarm indicator TP is connected in parallel with the coil of the second relay KA2.

[0010] Furthermore, it also includes a manual alarm cut-off switch SA3, one end of which is connected to the positive terminal of BAT, and the other end is connected to the normally open contact KA2-O of the second relay.

[0011] Furthermore, it also includes an emergency stop button JT and a fourth relay KA4. One end of the emergency stop button JT is connected to the positive terminal of BAT, and the other end is connected to the coil of the fourth relay KA4. The coil of the fourth relay KA4 is also connected to the negative terminal of the power supply BAT. The first normally open contact KA4-1C of the fourth relay is connected to the start button SB1, and the second normally open contact KA4-2C of the fourth relay is connected to the normally closed contact KA3-C of the third relay.

[0012] Furthermore, it also includes a power switch SA4, one end of which is connected to the start switch SA1, and the other end is connected to the positive terminal of the power supply BAT.

[0013] The beneficial technical effects of this invention are as follows:

[0014] (1) The present invention is provided with a first relay KA1. During the startup process, the first relay KA1 is energized and the normally open contact KA1-O of the first relay is closed. Even if the normally closed contact KA3-C of the third relay is opened during the low oil pressure process of the startup phase, the startup signal and idle / full speed signal can still be input to the diesel generator set through the normally open contact KA1-O of the first relay, thereby overcoming the problem that the diesel engine set cannot start normally due to the third relay KA3 performing the shutdown protection action during the startup phase.

[0015] (2) This invention does not restrict the oil pressure alarm signal to be connected to the power supply only during the full-speed stage. Instead, it can be connected to the power supply after the diesel generator set is powered on to perform low oil pressure detection. Therefore, if there is a low oil pressure fault in the unit during the startup process, the unit can also issue a low oil pressure alarm in time to remind the operator to manually stop the machine and indicate the fault type, so that the operator can troubleshoot the fault. If there is no low oil pressure fault in the unit, the low oil pressure alarm signal can also indicate whether the unit has gradually increased the oil pressure through the oil valve to meet the full-speed operation conditions during the idling stage, so that the operator can judge whether a full-speed signal can be issued to avoid damaging the unit and shortening the service life of the unit. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a circuit schematic diagram of an embodiment of the present invention. Detailed Implementation

[0018] To better understand the above-described objects, features, and advantages of the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the invention; however, the invention may be practiced in other ways different from those described herein, and therefore, the invention is not limited to the specific embodiments disclosed below.

[0019] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art described herein. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” “right,” etc., are used only to indicate relative positional relationships, which change accordingly when the absolute position of the described object changes.

[0020] like Figure 1 As shown, a diesel generator set oil pressure alarm circuit is characterized by comprising a power supply BAT, a starting module, an alarm cut-off module, and an oil pressure alarm protection module.

[0021] The starting module includes a start switch SA1, a start button SB1, and an idle-full speed switch SA2. The start switch SA1 has a first power supply branch and a second power supply branch. The first power supply branch is used to input the oil valve start signal and the idle / full speed signal, while the second power supply branch is used to input the start signal. One end of the first and second power supply branches is connected to the positive terminal of the power supply BAT, and the other end of the second power supply branch is connected to the start button SB1. The start switch SA1 is used to switch the unit's operating state, including three states: stop, start, and run. In the stop state, neither the first nor the second power supply branch is connected to the power supply BAT; in the run state, the first power supply branch is connected to the power supply BAT, and the second power supply branch is not connected; in the start state, both the first and second power supply branches are connected to the power supply BAT.

[0022] The alarm cutoff module includes a first relay KA1. One end of the coil of the first relay KA1 is connected to the start button SB1, and the other end is connected to the negative terminal of the power supply BAT. One end of the normally open contact KA1-O of the first relay is connected to the other end of the first power supply branch, and the other end is connected to the idle-full speed switch SA2. In the start state, the coil of the first relay KA1 is energized, and the normally open contact KA1-O of the first relay is closed. In the running or shutdown state, the coil of the first relay KA1 is de-energized, and the normally open contact KA1-O of the first relay is open.

[0023] The oil pressure alarm protection module includes an oil pressure sensor YY, a second relay KA2, a third relay KA3, and an alarm indicator TP. The oil pressure sensor YY is used to detect the oil pressure of the diesel generator set. The oil pressure sensor YY has a normally open contact that closes when the generator set's oil pressure is below a threshold. One end of the oil pressure sensor YY is connected to the coil of the second relay KA2, and the other end is connected to the negative terminal of the power supply BAT. The other end of the coil of the second relay KA2 is connected to the positive terminal of BAT. One end of the normally open contact KA2-O of the second relay is connected to the positive terminal of BAT, and the other end is connected to the coil of the third relay KA3. The coil of the third relay KA3 is also connected to the negative terminal of the power supply BAT. The normally closed contact KA3-C of the third relay is connected in parallel with the normally open contact KA1-O of the first relay. The alarm indicator TP is connected in parallel with the coil of the second relay KA2. When the unit is in a low oil pressure state, the coils of the second relay KA2 and the third relay KA3 are energized, the alarm indicator TP sends a low oil pressure alarm signal, the normally closed contact KA3-C of the third relay opens, and the unit performs a low oil pressure protection action, i.e., a shutdown operation, stopping the oil valves and engine from working. In this embodiment of the invention, the alarm indicator TP can be an alarm with audible or visual signals, or a display that can show fault signals or fault types, etc.

[0024] In this embodiment of the invention, a power switch SA4 is provided. One end of the power switch SA4 is connected to the start switch SA1, and the other end is connected to the positive terminal of the power supply BAT, used to control the power supply of this embodiment. To ensure the safe start-up and operation of the unit, this embodiment also includes a manual alarm cut-off switch SA3, an emergency stop button JT, and a fourth relay KA4. One end of the manual alarm cut-off switch SA3 is connected to the positive terminal of BAT, and the other end is connected to the normally open contact KA2-O of the second relay. The manual alarm cut-off switch SA3 can act as a backup circuit for the alarm cut-off module, replacing the function of the first relay KA1 when it fails. During the start-up phase, it manually cuts off the low oil pressure protection action to ensure the normal start-up of the unit. After successful start-up, the third relay KA3 is manually connected to execute the low oil pressure protection action when a low oil pressure fault occurs. One end of the emergency stop button JT is connected to the positive terminal of BAT, and the other end is connected to the coil of the fourth relay KA4. The coil of the fourth relay KA4 is also connected to the negative terminal of the power supply BAT. The first normally open contact KA4-1C of the fourth relay is connected to the start button SB1, and the second normally open contact KA4-2C of the fourth relay is connected to the normally closed contact KA3-C of the third relay. The emergency stop button JT is used to manually execute the low oil pressure protection action when the third relay KA3 fails.

[0025] The working principle of this invention is as follows:

[0026] Connect the other end of the idle-full speed switch SA2 to the electronic speed governor. Connect the other ends of the first normally open contact KA4-1C and the second normally open contact KA4-2C of the fourth relay to the engine and fuel valve, respectively. Press the power switch SA4 to connect the power supply BAT, and the diesel engine set will be powered on. Initially, the idle-full speed switch SA2 is in the off state.

[0027] After the diesel engine is powered on, because the unit is in a low oil pressure state, the normally open contact of the oil pressure sensor YY closes, energizing the coil of the second relay KA2 and the alarm indicator TP. The alarm indicator TP sends a low oil pressure alarm signal. At the same time, the normally open contact KA2-O of the second relay closes, energizing the coil of the third relay KA3. The third relay KA3 then performs a low oil pressure alarm protection action, opening the normally closed contact KA3-C of the third relay. Switch the start switch SA1 to the start state and press the start button SB1. At the same time, switch the idle-full speed switch SA2 to the idle state. Both the first power supply branch and the second power supply branch are connected to the power supply BAT. The engine receives the start signal and starts working. At the same time, the coil of the first relay KA1 is energized, and the normally open contact KA1-O of the first relay closes. The oil valve can be connected to the first power supply branch through the branch where the normally open contact KA1-O of the first relay is located, receive the oil valve start signal and start working. This avoids the third relay KA3 from performing a low oil pressure alarm protection action during the start-up phase, which would prevent the oil valve from working properly and affect the normal start-up of the unit. The electronic speed governor also receives the idle speed signal through the branch where the normally open contact KA1-O of the first relay is located and controls the idle speed operation of the unit.

[0028] Observe the low oil pressure alarm signal on the alarm indicator TP. When the oil pressure meets the full-speed requirement, the normally open contact of the oil pressure sensor YY opens, the coil of the second relay KA2 and the alarm indicator TP are de-energized, and the low oil pressure alarm signal disappears. At the same time, the normally open contact KA2-O of the second relay opens, causing the coil of the third relay KA3 to be de-energized. The third relay KA3 ends its low oil pressure alarm protection action and closes its normally closed contact KA3-C. At this time, switch the start switch SA1 to the running state. Although the coil of the first relay KA1 is de-energized and the normally open contact KA1-O of the first relay is open, the oil valve and the electronic speed governor can still maintain normal operation through the branch where the normally closed contact KA3-C of the third relay is located. At this time, switch the idle-full speed switch SA2 to the full-speed state, and send the full-speed signal to the electronic speed governor through the branch where the normally closed contact KA3-C of the third relay is located. The unit can enter the full-speed running state and complete the unit startup. If the low oil pressure alarm signal on the alarm indicator TP does not disappear, it indicates that there is a low oil pressure fault in the unit. The unit should be shut down immediately for troubleshooting. Do not operate the idle-full speed switch SA2 to put the unit into full speed mode.

[0029] If the first relay KA1 malfunctions, the low oil pressure alarm protection can be manually deactivated during the startup phase using the manual alarm cut-off switch SA3. Specifically, after powering on the diesel generator set, press the manual alarm cut-off switch SA3, then switch the start switch SA1 to the start position, press the start button SB1, and switch the idle-full speed switch SA2 to the idle position. At this time, because the normally closed contact of the manual alarm cut-off switch SA3 opens, the coil of the third relay KA3 is de-energized, and the third relay KA3 terminates the low oil pressure alarm protection action. Therefore, the oil valve and electronic governor can also function normally. After the low oil pressure alarm signal disappears, press the manual alarm cut-off switch SA3 again. Because the normally open contact KA2-O of the second relay opens, the coil of the third relay KA3 remains de-energized, and the normally closed contact KA3-C of the third relay remains closed. Switching the start switch SA1 to the running position and switching the idle-full speed switch SA2 to the full speed position will also successfully complete the generator start-up.

[0030] During unit operation, if a low oil pressure fault occurs, the normally open contact of the oil pressure sensor YY closes, energizing the coil of the second relay KA2 and the alarm indicator TP. The alarm indicator TP then issues a low oil pressure alarm signal. Simultaneously, the normally open contact KA2-O of the second relay closes, energizing the coil of the third relay KA3. The third relay KA3 then performs a low oil pressure alarm protection action, opening its normally closed contact KA3-C. At this time, the oil valve can no longer receive the oil valve start signal, and the electronic speed governor can no longer receive the idle / full speed signal. The unit stops operating to prevent damage. Operators can quickly identify the fault type based on the alarm signal type issued by the alarm indicator TP, thus quickly troubleshooting and restoring the unit to normal operation. Before the low oil pressure fault is cleared, the normally open contact of the oil pressure sensor YY remains closed, and the low oil pressure alarm signal will persist until the fault is cleared, the normally open contact of the oil pressure sensor YY opens, and the low oil pressure alarm signal disappears.

[0031] If the third relay KA3 fails to perform the low oil pressure protection action in time, the operator can use the emergency stop button JT to stop the machine in an emergency. After pressing the emergency stop button JT, the normally open contact of the emergency stop button JT closes, the coil of the fourth relay KA04 is energized, the first normally open contact KA4-1C and the second normally open contact KA4-2C of the fourth relay open, the engine and oil valve stop working, and the unit enters the emergency stop state. The operator can use a multimeter and other instruments to check whether the third relay KA3 is faulty.

[0032] During normal shutdown, switch the start switch SA1 to the shutdown state. Neither the first nor the second power supply branch is connected to the power supply BAT. The engine and oil valve stop working, completing the shutdown. Then, reset the idle-full speed switch SA2 to the shutdown state and press the power switch SA4 to cut off the power supply BAT.

[0033] In summary, because this embodiment of the invention does not restrict the oil pressure alarm signal to be connected to the power supply only during the full-speed stage, but allows connection to the power supply and low oil pressure detection immediately after the diesel generator set is powered on, if a low oil pressure fault occurs during startup, the unit can promptly issue a low oil pressure alarm, reminding the operator to manually stop the machine and indicating the fault type, facilitating troubleshooting. If there is no low oil pressure fault, the low oil pressure alarm signal can also indicate whether the oil pressure has been gradually increased through the oil valve to meet the full-speed operating conditions during the idling stage, allowing the operator to determine whether a full-speed signal can be issued, thus avoiding damage to the unit and shortening its service life. Furthermore, through the first relay KA1, this embodiment of the invention successfully overcomes the problem of the diesel engine set failing to start normally due to the third relay KA3 performing a shutdown protection action during the startup stage.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A diesel generator set oil pressure alarm circuit, characterized in that, This includes the power supply BAT, startup module, alarm cut-off module, and oil pressure alarm protection module; The starting module includes a start switch SA1, a start button SB1, and an idle-full speed switch SA2. The start switch SA1 is provided with a first power supply branch and a second power supply branch. One end of the first power supply branch and the second power supply branch are connected to the positive terminal of the power supply BAT, and the other end of the second power supply branch is connected to the start button SB1. The start switch SA1 has three states: stop, start, and run. In the stop state, neither the first power supply branch nor the second power supply branch is connected to the power supply BAT. In the run state, the first power supply branch is connected to the power supply BAT, and the second power supply branch is not connected to the power supply BAT. In the start state, both the first power supply branch and the second power supply branch are connected to the power supply BAT. The alarm cut-off module includes a first relay KA1. One end of the coil of the first relay KA1 is connected to the start button SB1, and the other end is connected to the negative terminal of the power supply BAT. One end of the normally open contact KA1-O of the first relay is connected to the other end of the first power supply branch, and the other end is connected to the idle-full speed switch SA2. The oil pressure alarm protection module includes an oil pressure sensor YY, a second relay KA2, a third relay KA3, and an alarm indicator TP. One end of the oil pressure sensor YY is connected to the coil of the second relay KA2, and the other end is connected to the negative terminal of the power supply BAT. The other end of the coil of the second relay KA2 is connected to the positive terminal of BAT. One end of the normally open contact KA2-O of the second relay is connected to the positive terminal of BAT, and the other end is connected to the coil of the third relay KA3. The coil of the third relay KA3 is also connected to the negative terminal of the power supply BAT. The normally closed contact KA3-C of the third relay is connected in parallel with the normally open contact KA1-O of the first relay. The alarm indicator TP is connected in parallel with the coil of the second relay KA2.

2. The diesel generator set oil pressure alarm circuit according to claim 1, characterized in that, It also includes a manual alarm cut-off switch SA3, one end of which is connected to the positive terminal of BAT, and the other end is connected to the normally open contact KA2-O of the second relay.

3. The diesel generator set oil pressure alarm circuit according to claim 1, characterized in that, It also includes an emergency stop button JT and a fourth relay KA4. One end of the emergency stop button JT is connected to the positive terminal of BAT, and the other end is connected to the coil of the fourth relay KA4. The coil of the fourth relay KA4 is also connected to the negative terminal of the power supply BAT. The first normally open contact KA4-1C of the fourth relay is connected to the start button SB1, and the second normally open contact KA4-2C of the fourth relay is connected to the normally closed contact KA3-C of the third relay.

4. The diesel generator set oil pressure alarm circuit according to claim 1, characterized in that, It also includes a power switch SA4, one end of which is connected to the start switch SA1, and the other end is connected to the positive terminal of the power supply BAT.

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