Engine-driven generator and its control method

Abstract

In cold climates, this prevents the engine of an engine-driven generator from being started while the coolant, engine oil, gaskets, etc., are still at low temperatures, thus preventing the engine from being subjected to a high load while it is still cold. [Solution] The diesel engine generator 1 includes an engine, a load bank (heater 20) that applies a load to the engine to promote warm-up, an intake air temperature sensor 21 that detects the engine cleaner intake air temperature, a water temperature sensor 21 that detects the engine coolant temperature, an engine control module 11 that controls the engine and detects the engine status, and a main control unit 12 that switches the operation or stopping of the heater 20 based on information from the intake air temperature sensor and the water temperature sensor. The main control unit operates the heater 20 when all predetermined conditions are met, such as the engine speed, the intake air temperature detected by the intake air temperature sensor, and the water temperature detected by the water temperature sensor, or stops the heater 20 when any of the predetermined conditions are met.

Description

[Technical Field]

[0001] The present invention relates to an engine-driven generator and a control method therefor. [Background Art]

[0002] Conventionally, there has been no additional function for warming up, and it has been necessary to wait with the engine running at no load until the engine warms up. At low temperatures, the viscosity of engine oil is high. If a high load is applied to the engine before the oil sufficiently spreads inside the engine, friction between components increases, placing a large burden on the engine, and repeated such forced operation over a long period of time shortens the engine service life. Although it is possible to forcibly raise the water temperature by idling with the throttle open or applying a light load, an operator has to perform labor-intensive work for this purpose. On the other hand, if the operator does not go to such extra trouble and applies a high load to the cold engine over a long period of time, there is a problem that the engine service life may be significantly shortened and the risk of damage also increases.

[0003] To address this problem, as disclosed in, for example, Patent Document 1, there is known an engine warm-up promotion device for an engine generator, in which a warm-up promotion load means is interlockingly connected to at least one of the engine and the generator of the engine generator via a power connecting / disconnecting means, the power connecting / disconnecting means is linked to a warm-up completion temperature detection means, the warm-up completion temperature detection means performs disconnection and connection operations of the power connecting / disconnecting means based on detecting the engine temperature, the power connecting / disconnecting means is operated to connect when the detected temperature is lower than a set warm-up completion temperature, and the power connecting / disconnecting means is operated to disconnect when the detected temperature is higher than the set warm-up completion temperature. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 3-37331 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] However, in the case of Patent Document 1, external load output is not possible during warm-up if the temperature is within the set range. Also, because the temperature changes of air and water are small and change slowly, if there is a sudden load change, the engine output may not be able to keep up, which could cause the engine to stop.

[0006] The present invention has been made in view of the above, and its purpose is to prevent the engine from being subjected to a high load while it is cold, by starting the engine with the coolant, engine oil, gaskets, etc., still at a low temperature in cold regions. [Means for solving the problem]

[0007] To achieve the above objective, this invention appropriately utilizes the load bank (heater load, etc.) to warm up the engine quickly and efficiently.

[0008] Specifically, in the first invention, The engine and A load bank that applies a load to the engine to promote warm-up, An intake air temperature sensor for detecting the intake air temperature of the engine cleaner, A water temperature sensor for detecting the coolant temperature of the engine, An engine control module that controls the engine and detects the state of the engine, The system includes a main control unit that switches the operation or stopping of the load bank based on information from the intake air temperature sensor and the water temperature sensor, The main control unit is configured to operate the load bank when all predetermined conditions are met, such as the engine speed, the intake air temperature detected by the intake air temperature sensor, and the water temperature detected by the water temperature sensor, or to stop the load bank when any of the predetermined conditions are met.

[0009] According to the above configuration, the load bank is automatically switched ON / OFF at the appropriate timing when all predetermined conditions are met, such as engine speed, intake air temperature detected by the intake air temperature sensor, and water temperature detected by the water temperature sensor. This reduces engine damage, lowers maintenance costs for parts that previously had short lifespans, contributes to improved operational efficiency by shortening warm-up time, prevents incomplete combustion at low temperatures, reduces exhaust emissions, and improves fuel efficiency.

[0010] In the second invention, in the first invention, The main control unit is The engine speed remains at 90% or more of the rated speed for 2 minutes. The cleaner intake air temperature remains below -5°C for 2 minutes or more. Furthermore, if the cooling water temperature remains below 70°C for 2 minutes or more, The system is configured to initiate the operation of the load bank.

[0011] With the above configuration, the load bank can be automatically started at the appropriate time, reducing engine damage and lowering maintenance costs for parts that previously had short lifespans. It also contributes to improved operational efficiency by shortening warm-up time.

[0012] In the third invention, in the first or second invention, The main control unit is The rotational speed of the aforementioned engine drops to less than 90% of the rated rotational speed. Alternatively, if the cleaner intake air temperature remains at -5°C or higher for 2 minutes or more, Or, if the cooling water temperature remains above 70°C for 2 minutes or more, The load bank is configured to stop operating.

[0013] According to the above configuration, stopping the operation of the load bank for warm-up operation as soon as it is no longer necessary can prevent unnecessary fuel consumption and output reduction. In addition, if an external load is connected unexpectedly and the combined load of the load bank and the external load exceeds the rated load of the generator, a reduction in rotational speed is detected and the load bank is turned off instantaneously, so that priority can be given to the external load.

[0014] In a fourth aspect of the invention, in any one of the first to third aspects of the invention, the load bank is a heater, and the load bank comprises a load bank ON / OFF switch that enables manual ON / OFF operation of the heater.

[0015] According to the above configuration, enabling manual operation of the heater also allows forced disabling of the operation of the heater serving as the load bank. In addition, an operator can switch the state only when necessary, and when the switch is ON, the heater reliably operates if conditions are satisfied.

[0016] An invention of a fifth control method for an engine-driven generator is directed to an engine, a load bank that applies a load to the engine to promote warm-up, an intake air temperature sensor that detects cleaner intake air temperature of the engine, a water temperature sensor that detects cooling water temperature of the engine, an engine control module that controls the engine and detects a state of the engine, a control method for an engine-driven generator, the generator comprising a main control unit that switches between operation and stop of the load bank based on information from the intake air temperature sensor and the water temperature sensor, in the control method, when the rotational speed of the engine continues to be 90% or more of the rated rotational speed for 2 minutes or more, the cleaner intake air temperature continues to be lower than -5°C for 2 minutes or more, and the cooling water temperature continues to be lower than 70°C for 2 minutes or more, operation of the load bank is started, when the rotational speed of the engine drops below 90% of the rated rotational speed, or when the cleaner intake air temperature continues to be -5°C or higher for 2 minutes or more, or when the cooling water temperature continues to be 70°C or higher for 2 minutes or more, the load bank is configured to stop operation.

[0017] According to the above configuration, automatically performing ON / OFF control of the heater at an appropriate timing when all of the engine rotational speed, the intake air temperature detected by the intake air temperature sensor, and the water temperature detected by the water temperature sensor all satisfy predetermined conditions reduces damage to the engine, which not only reduces maintenance costs for components that would otherwise have shortened service lives, but also contributes to improving working time efficiency by shortening warm-up time. By stopping the operation of the load bank immediately when it is no longer required for warm-up operation, unnecessary fuel consumption and output reduction can be prevented.

[0018] In a sixth invention, in the fifth invention, after stopping the operation of the load bank when the rotational speed of the engine drops below 90% of the rated rotational speed, or when the cleaner intake air temperature continues to be -5°C or higher for 2 minutes or more, or when the cooling water temperature continues to be 70°C or higher for 2 minutes or more, when the rotational speed of the engine again continues to be 90% or more of the rated rotational speed for 2 minutes or more, the cleaner intake air temperature continues to be lower than -5°C for 2 minutes or more, and the cooling water temperature continues to be lower than 70°C for 2 minutes or more, the operation of the load bank is started.

[0019] According to the above configuration, when the load bank is ON, a large load such as an inductive load is applied as an external load, causing the engine rotational speed to drop instantaneously and turning the load bank OFF; however, when the external load stabilizes, the required power supply amount decreases, and the engine rotational speed also rises to reach the rated rotation. At that time, if the intake air temperature and the cooling water temperature again satisfy all of the above conditions, the load bank is turned ON again to promote warm-up. Effects of the Invention

[0020] As explained above, the present invention reduces engine damage, not only lowering maintenance costs for parts with shortened lifespans, but also contributing to improved operational efficiency by shortening warm-up time. [Brief explanation of the drawing]

[0021] [Figure 1] This is a schematic diagram showing an engine-type generator according to an embodiment of the present invention. [Figure 2] Block diagram showing an engine-driven generator according to an embodiment of the present invention. [Figure 3] This is a functional block diagram showing an engine-type generator according to an embodiment of the present invention. [Figure 4] This flowchart shows the control flow of an engine-type generator according to an embodiment of the present invention. [Modes for carrying out the invention]

[0022] Embodiments of the present invention will be described below with reference to the drawings.

[0023] -Device configuration- Figures 1 to 3 show a diesel engine generator 1 according to an embodiment of the present invention. This diesel engine generator 1 comprises a rectangular parallelepiped housing 2 and a base portion 3 at its lower part. A diesel engine 4 and a generator 5 driven by it are mounted on this base portion 3. Although not shown, the diesel engine generator 1 also has other components necessary for power generation, such as a fuel tank.

[0024] A muffler 6 (exhaust gas aftertreatment device) is connected to the diesel engine 4 for exhaust treatment, so that the exhaust gas is discharged to the outside.

[0025] Inside the enclosure 2 are the control box 10 and the heater 20, which acts as a load bank. The heater 20 plays a role in applying a load to the diesel engine 4 to promote warm-up. The position of the heater 20 is not limited to the position shown in Figure 1.

[0026] The control box 10 includes an ECM 11 (engine control device), a main control unit 12, an output control unit 13 that receives signals from the load bank switch 15, a relay 14, an electromagnetic contactor 16, a cam switch 17, a circuit breaker 18, and the like. The load bank switch 15 is a manual switch that controls the operation of the heater 20 and is located in an easily accessible place on the housing 2. The power supply between each device is, for example, 3-phase 240V or 480V.

[0027] The ECM11 is a commercially available engine control module compatible with a diesel engine 4, and includes an intake air temperature sensor / coolant temperature sensor 21 for detecting intake air temperature and coolant temperature, and a function for detecting engine speed. The intake air temperature sensor and coolant temperature sensor may each be provided separately in appropriate locations.

[0028] The main control unit 12 is composed of, for example, a microcontroller CPU, and controls the operation / stopping of the heater 20 based on information from each sensor.

[0029] The output control unit 13 consists of a circuit board and the like, in particular, for controlling the output of the heater 20.

[0030] -Control Procedure- Next, the control procedure for the engine-driven generator 1 according to this embodiment will be explained with reference to Figure 4.

[0031] First, when the main power to the diesel engine generator 1 is turned on, the diesel engine 4 starts and stabilizes at an idling speed (for example, 1000 rpm).

[0032] In step S01, the ON / OFF status of the load bank switch 15 is determined. If the load bank switch 15 is OFF, the normal operation in step S11 continues. For example, in the normal operation state of the diesel engine 4, the rated rotation speed (high rotation) is set to 1500 rpm at 50 Hz and 1800 rpm at 60 Hz. If the load bank switch 15 is ON, the process proceeds to step S02.

[0033] In step S02, the heater 20 starts operating when the load bank switch 15 is ON and all three of the following conditions are met.

[0034] Specifically, the system determines whether the engine speed remains at 1620 rpm for 2 minutes or longer at 60Hz, or at 1350 rpm for 2 minutes or longer at 50Hz. Furthermore, it determines whether the air cleaner intake temperature remains below -5°C for 2 minutes or longer, and whether the coolant temperature remains below 70°C for 2 minutes or longer. If all three conditions are met, the system proceeds to step S03 and the electromagnetic contactor 16 is engaged. As long as the three conditions are not met, and the load bank switch 15 is ON, the determination in step S02 is repeated.

[0035] Next, the process proceeds to step S04, where the heater 20 is powered on, and then the process proceeds to step S05.

[0036] In step S05, the ON / OFF status of the load bank switch 15 is determined again. If the switch is manually turned OFF, the electromagnetic contactor 16 is turned OFF in step S06, and the power to the heater 20 is turned OFF in step S10. If it remains ON, the process proceeds to step S07.

[0037] In step S07, the engine speed is determined. Specifically, if the engine speed drops even momentarily to below 1620 rpm at 60Hz or below 1350 rpm at 50Hz, the process proceeds to step S06, and the heater 20 stops in step S10. If the engine speed remains above the aforementioned speed, the process proceeds to step S08.

[0038] In step S08, it is determined whether the cleaner intake air temperature has remained at -5°C or higher for 2 minutes or more. If it has remained at -5°C or higher for 2 minutes or more, it is determined that warming up has progressed, and the process proceeds to step S06. If it has not remained at -5°C or higher, the process proceeds to step S09.

[0039] In step S09, it is determined whether the coolant temperature has remained above 70°C for more than 2 minutes. If it has, it is determined that warming up has progressed, and the process proceeds to step S06. If it has not, the process returns to step S05, and the determination is repeated, maintaining the ON state of the heater 20.

[0040] Then, in step S06, the contactor is turned off, the heater 20 stops in step S10, and the process returns to the judgment in step S02. In this way, if an external load is applied and the combined load of the heater 20 and the external load exceeds the rated load of the generator 5, the decrease in rotational speed is detected, the heater 20 is instantly turned OFF, and the external load can be given priority.

[0041] Then, when the heater 20 is ON, a large external load such as an inductive load is applied, causing the engine speed to momentarily drop, and the heater 20 is turned OFF. However, once the external load stabilizes, the required power supply decreases, and the engine speed increases to its rated speed. At that time, if the intake air temperature and coolant temperature again meet all the aforementioned conditions, the heater 20 is turned ON again to promote warm-up.

[0042] This invention makes it possible to efficiently warm up the engine in cold weather. By controlling a combination of three elements—intake air temperature, coolant temperature, and engine speed—the system automatically recognizes low-temperature environments, optimizes the operation timing of the heater 20 to minimize waste, and reduces the load on the diesel engine 4 and related components.

[0043] This will result in the following effects:

[0044] (1) Extending the lifespan of the diesel engine 4: By avoiding high-load operation in low-temperature conditions, wear and damage to the diesel engine 4 and its components can be prevented.

[0045] (2) Reduced warm-up time: By utilizing the load from the heater 20, the optimal temperature can be reached in a shorter time than with conventional idling warm-up.

[0046] (3) Reduction of unnecessary work for warming up: Without the need for extra work such as revving the engine to shorten the warm-up time, the system can automatically recognize the low-temperature environment and optimally apply the heater load, and automatically shut off when warm-up is complete.

[0047] (4) Avoiding engine malfunction in low-temperature environments: If the temperature of the diesel engine 4 does not rise and malfunction occurs, causing the engine speed to drop, turning off the heater 20 prevents the diesel engine 4 from stopping unintentionally and ensures stable operation as a generator.

[0048] These effects significantly improve the reliability and efficiency of engine operation in cold climates and contribute to reducing maintenance costs.

[0049] Therefore, according to the engine-driven generator 1 of this embodiment, damage to the diesel engine 4 is reduced, which not only reduces maintenance costs for parts that had a short lifespan but also contributes to improved operational efficiency by shortening the warm-up time.

[0050] (Other embodiments) The present invention may also have the following configuration in the above embodiment.

[0051] In other words, although the above embodiment uses a heater 20 as the load bank, it is not limited to this, and any device that intentionally applies a load to the diesel engine 4 to promote warming up is acceptable. Possible devices that apply a load include electrical resistance loads and water resistance loads.

[0052] In the above embodiment, a microcomputer was described as an example of the main control unit 12 / output control unit 13. However, the main control unit 12 / output control unit 13 controls the diesel engine generator 1 / heater 20 and can be physically configured in any way as long as it has a CPU (processor) and memory. For example, the main control unit 12 / output control unit 13 may utilize software (programs), such as a microcomputer or a programmable logic controller (PLC). Alternatively, the main control unit 12 / output control unit 13 may be realized by combining hardware (circuit components).

[0053] The embodiments described above are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses. [Explanation of Symbols]

[0054] 1. Diesel engine generator 2 cabinets 3. Base section 4 Diesel engine 5 Generators 6. Muffler (exhaust gas aftertreatment device) 10 Control Boxes 11 ECM 12 Main control unit 13 Output control unit 14 Relay 15. Load Bank Switch 16 Electromagnetic Contactor 17 Cam switch 18 Breaker 20 Heaters 21. Intake air temperature sensor / Water temperature sensor

Claims

1. The engine and A load bank that intentionally applies a load to the engine to promote warm-up, A load bank switch for manually allowing or disabling the operation of the load bank, An intake air temperature sensor for detecting the intake air temperature of the engine cleaner, A water temperature sensor for detecting the coolant temperature of the engine, An engine control module that controls the engine and detects the state of the engine, The system includes a main control unit that switches the operation or stopping of the load bank based on information from the intake air temperature sensor and the water temperature sensor, The main control unit is With the load bank switch ON, The engine's rotational speed remains at 90% or more of its rated rotational speed for two minutes or more. The cleaner intake air temperature remains below -5°C for 2 minutes or more. Furthermore, if the cooling water temperature remains below 70°C for two minutes or more, The load bank starts operation, During the operation of the aforementioned load bank, The rotational speed of the aforementioned engine drops to less than 90% of the rated rotational speed. Alternatively, if the cleaner intake air temperature remains at -5°C or higher for 2 minutes or more, Or, if the cooling water temperature remains above 70°C for two minutes or more, The operation of the aforementioned load bank is stopped, When the load bank switch is OFF, the load bank is not operated and normal operation continues. An engine-driven generator characterized by the following features.

2. After stopping the operation of the load bank when the engine speed drops to less than 90% of the rated speed, or the cleaner intake air temperature remains at -5°C or higher for 2 minutes or more, or the coolant temperature remains at 70°C or higher for 2 minutes or more, The load bank is configured to start operating again when the engine speed remains at 90% or more of the rated speed for 2 minutes or more, the cleaner intake air temperature remains below -5°C for 2 minutes or more, and the coolant temperature remains below 70°C for 2 minutes or more. The engine-driven generator according to feature 1.

3. The aforementioned load bank is a heater. The engine-driven generator according to claim 1 or 2.

4. The engine and A load bank that intentionally applies a load to the engine to promote warm-up, A load bank switch for manually allowing or disabling the operation of the load bank, An intake air temperature sensor for detecting the intake air temperature of the engine cleaner, A water temperature sensor for detecting the coolant temperature of the engine, An engine control module that controls the engine and detects the state of the engine, A control method for an engine-type generator, comprising a main control unit that switches the operation or stopping of the load bank based on information from the intake air temperature sensor and the water temperature sensor, In the aforementioned control method, With the load bank switch ON, The engine's rotational speed remains at 90% or more of its rated rotational speed for two minutes or more. The cleaner intake air temperature remains below -5°C for 2 minutes or more. Furthermore, if the cooling water temperature remains below 70°C for two minutes or more, The load bank starts operation, During the operation of the aforementioned load bank, The rotational speed of the aforementioned engine drops to less than 90% of the rated rotational speed. Alternatively, if the cleaner intake air temperature remains at -5°C or higher for 2 minutes or more, Or, if the cooling water temperature remains above 70°C for two minutes or more, The operation of the aforementioned load bank is stopped, If the load bank switch is OFF, the load bank will not be operated and normal operation will continue. A control method for an engine-driven generator, characterized by the features described herein.

5. After the load bank operation is stopped when the engine speed drops to less than 90% of the rated speed, or the cleaner intake air temperature remains at -5°C or higher for two minutes or more, or the coolant temperature remains at 70°C or higher for two minutes or more, The load bank will start operating again if the engine speed remains at 90% or more of the rated speed for 2 minutes or more, the cleaner intake air temperature remains below -5°C for 2 minutes or more, and the coolant temperature remains below 70°C for 2 minutes or more. The control method for an engine-driven generator according to feature 4.

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