JP5530208B2 - Engine and engine generator system - Google Patents

Description

  The present invention relates to an engine and an engine generator system, and more particularly to an engine overheat prevention configuration employed in a cogeneration apparatus.

  For example, in an engine generator, a configuration in which overheating is prevented by limiting output power in accordance with cooling water temperature is known (see, for example, Patent Document 1). In the configuration described in Patent Document 1, two categories of cooling water temperature ranges (103 degrees or more and less than 104 degrees, 104 degrees or more and less than 105 degrees) are set, and each cooling water temperature range has a high temperature. The limit power values of 9 kW and 8 kW are set so that the limit power value decreases step by step.

JP 2005-76566 A

  The said patent document 1 is the structure which reduces a limit value in steps according to cooling water temperature. As a result, the limit power set value decreases as the cooling water temperature increases, and there is a problem that the effect of performing the cool-down while suppressing the output of the engine is small.

  Therefore, the present invention presents an engine overheat failure prevention configuration with a greater cool-down effect.

The present invention has been made to solve the above-described problems, and outputs when it is detected that at least one element of the coolant temperature, the lubricant temperature, the supply air temperature, or the fuel temperature is equal to or higher than a set value. In an engine having an operation control device for controlling
When continuously detecting that at least one of the cooling water temperature, lubricating oil temperature, supply air temperature, or fuel temperature is equal to or higher than the set value for a predetermined time, the output is a predetermined value regardless of the detected element. hereinafter limited to uniform, when the temperature of the sensing element or elements is at least the set value is detected that is less than the set value in the output limiting state is to be returned to output of the previous stage limiting.

  In the present invention, the output is not limited stepwise by the cooling water temperature as in the prior art, but at least one element of the cooling water temperature, the lubricating oil temperature, the supply air temperature, or the fuel temperature caused by the engine load. When it is detected that is equal to or greater than the set value, the output is uniformly limited to a predetermined value, so that the cool-down effect is increased. In addition, since the output is restored in a stepwise manner, it is possible to prevent the occurrence of overheating problems due to the sudden increase in output.

  Further, in the engine power generation system in which a plurality of engine generators that drive a generator with the engine are operated in parallel, the present invention adds a generator stator temperature as a temperature monitoring element and disconnects the engine generator It is to preferentially disconnect the engine generator in the output limited state.

  The present invention can preferentially stop the engine generator on which overheating has occurred, and can prevent the engine from being stopped due to overheating.

  Further, the present invention is to calculate an engine output limit value based on a margin of received power with respect to contract power or manually set in an engine generator system.

  In the present invention, even when the engine output is controlled, the output can be limited within a range not exceeding the contract power. Moreover, in the case of manual operation, arbitrary output restrictions according to the operation site can be performed.

  The present invention uniformly limits the engine output to a predetermined value when at least one element of the cooling water temperature, the lubricating oil temperature, the supply air temperature, or the fuel temperature is equal to or higher than each set value. The effect can be increased. In addition, since the output is restored step by step, it is possible to prevent the occurrence of overheating problems due to the sudden increase in output.

It is the schematic of the engine generator which shows one Embodiment of this invention. It is the schematic which shows control of the engine generator. It is a schematic diagram of the engine generator system. (A) is a figure which shows the relationship between the detected temperature and operating time in the engine generator, (b) is a figure which shows the relationship between the generator output and operating time in the engine generator. It is a flowchart which shows operation | movement of the engine generator. It is a figure which shows the preset temperature of the temperature monitoring element of each part of the engine generator. It is a flowchart which shows operation | movement of the engine generator. It is the schematic which shows control of the engine generator.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1-6 shows one Embodiment which employ | adopted this invention for the engine generator system employ | adopted as a cogeneration apparatus.

  In the engine generator system, as shown in FIG. 3, a plurality of engine generators X are arranged in a system linkage in parallel. The engine generator X includes an engine 1 and a generator 56 driven by the engine 1. Further, the engine generator X is connected to a commercial power source (not shown) via the circuit breaker 59 and is also connected to the load device 57. The circuit breaker 59 is used to connect or shut off the engine generator X and the load-side power system.

  As shown in FIG. 1, the engine 1 is a gas engine that uses city gas (natural gas) as a power source, and includes a lubricating oil system 2 and a cooling water system 3.

  First, the lubricating oil system 2 will be described. The engine 1 is provided with an oil pan 5 in which lubricating oil is stored, and a lubrication path 20 for supplying the lubricating oil in the oil pan 5 to each part in the engine 1 to lubricate each part.

A strainer 21 is provided at the upstream end of the lubrication path 20 so as to be immersed in the lubricating oil in the oil pan 5. A lubricating oil pump 22 that pumps up lubricating oil through a strainer 21 is provided in the middle of the lubricating path 20. The lubricating oil pumped up by the lubricating oil pump 22 is cooled by the lubricating oil cooler 25 and then enters the engine 1 to cool and lubricate each part. The lubricating oil that has lubricated each part is designed to return to the oil pan 5.
Between the lubricating oil pump 22 and the lubricating oil cooler 25 in the lubricating path 20, a lubricating oil temperature sensor 26 that detects the temperature of the lubricating oil flowing through the lubricating path 20 is provided. The lubricant temperature sensor 26 detects the lubricant temperature before being cooled by the lubricant cooler 25 after being discharged from the lubricant pump 22.

  Since the temperature of the lubricating oil before being pumped up from the oil pan 5 and supplied to each part of the engine 1 reflects the temperature of the engine 1, it becomes one of the elements for measuring the load state of the engine 1. The sensor 26 can detect the load state of the engine 1 by detecting the temperature of the lubricating oil.

  Next, the cooling water system 3 will be described. Two cooling water systems 3 are provided independently. One cooling water system 30 is a cooling water system that cools each part of the engine 1 (for example, a cylinder block or a cylinder head (not shown)). The other cooling water system 31 is a cooling water system connected to an air supply cooler (intercooler) 34 for cooling the air compressed by the supercharger 33.

  One cooling water system 30 includes a cooling water path 37 through which the cooling water radiated by the radiator (first radiator) flows by the pump 36. The cooling water path 37 is branched, and one path 38 communicates with a jacket (not shown) provided in the engine 1. The cooling water flowing through one path 38 cools each part of the engine, and then flows through a return path (not shown) to return to the first radiator.

  The other path 39 is connected to the lubricating oil cooler 25, and the cooling water flowing through the other path 39 cools the lubricating oil flowing through the lubricating path 20 in the lubricating oil cooler 25. A return path 40 is connected to the lubricating oil cooler 25, and the cooling water flows through the return path 40 and returns to the first radiator.

  In the return path 40, a cooling water thermistor 41 is provided as a cooling water temperature sensor. This cooling water temperature sensor 41 detects the cooling water temperature after cooling the lubricating oil in the lubricating oil cooler 25 and before radiating heat with the first radiator. Since the cooling water in such a portion actually passes through the jacket of the engine 1, the engine load (how the engine is warmed) is directly reflected. Therefore, the cooling water temperature after cooling the lubricating oil and before releasing heat by the first radiator is one of the elements for detecting the load state of the engine 1, and the lubricating oil temperature sensor 26 detects the cooling water temperature. By doing so, the load state of the engine 1 can be detected.

  The other cooling water system 31 circulates and moves the cooling water between the radiator (second radiator) and the supply air cooler 34, and cools the air compressed by the supercharger 33. A supply air temperature sensor 45 is connected to the supply air cooler 34. When the load on the engine 1 increases, the amount of fuel injection inevitably increases, so the temperature of the exhaust gas rises. Further, the rotational speed of the turbine 44 increases, and the amount of air sucked by the turbine 44 increases. As the air volume increases, the temperature is proportional to the density, so the air temperature increases.

  Therefore, the state of the engine load can be grasped from the temperature of the exhaust gas and the fuel injection condition. For this reason, the supply air temperature in the supply air cooler 34 is one of the elements for detecting the load state of the engine 1, and the supply air temperature sensor 45 detects the supply air temperature, thereby determining the load state of the engine 1. Can be detected.

  Since high pressure air is supplied to the engine 1 by the supercharger 33 to the engine 1 using city gas as a power source, it is necessary to pump high pressure fuel to the engine 1. Therefore, a fuel gas compressor 51 is provided. A fuel thermistor 50 as a fuel temperature sensor is provided in the outlet path 52 of the fuel gas compressor 51 to detect the fuel gas temperature.

  Further, when the fuel gas consumption increases, the rotation of the fuel gas compressor 51 increases and the temperature of the fuel gas also increases. Therefore, the temperature of the fuel gas is one element for detecting the load state of the engine 1, and the load state of the engine 1 can be detected by the fuel temperature sensor 50 detecting the temperature of the fuel gas.

  As shown in FIG. 2, the lubricating oil temperature sensor 26, the cooling water temperature sensor 41, the supply air temperature sensor 45, and the fuel temperature sensor 50 are connected to a controller 55 as a control unit. Signals 41, 45, and 50 are transmitted to the controller 55. The controller 55 controls the engine 1 based on the signals of the temperature sensors 26, 41.45, 50, and the output (hereinafter referred to as output) of the engine generator X operating at the rated power is set to a predetermined value or less. Perform load suppression control (rate down) to reduce. Each temperature sensor 26, 41, 45, 50 and the controller 55 constitute an operation control device 58.

  Next, the operation of the engine generator system configured as described above will be described with reference to the flowchart of the engine generator shown in FIG. In the description of the operation of the engine generator system, FIGS. 3, 4 and 6 are also referred to as appropriate. 4A shows the relationship between the detected temperature and the operating time in the engine generator X, FIG. 4B shows the relationship between the output and the operating time in the engine generator X, and FIG. 6 shows each temperature. Indicates the set temperature of the monitoring element.

  First, the breaker 59 of each engine generator X is connected, and power supply is started (S1). During normal power generation, the output reaches 100 percent of the rating.

  Then, it is determined whether or not load suppression for reducing the rated power of the engine generator X is necessary (S2). The load suppression determination is performed by determining whether or not any one of the coolant temperature, the lubricating oil temperature, the supply air temperature, or the fuel temperature has reached the temperature rise determination value R or more by using any one of the temperature monitoring elements.

  Specifically, signals detected by the lubricant temperature sensor 26, the coolant temperature sensor 41, the supply air temperature sensor 45, and the fuel temperature sensor 50 are transmitted to the controller 55. In the controller 55, set values of the lubricating oil temperature, the cooling water temperature, the supply air temperature, and the fuel temperature are stored in advance. Each specific set value is shown in FIG. In the figure, the light failure means a failure in which the controller 55 limits the output of the engine 1 when each temperature sensor detects the first set value of the low temperature side temperature. Then, the first set value of the low temperature side temperature becomes the temperature rise determination value R.

  The serious failure is a failure in which the controller 55 stops the engine 1 when each temperature sensor 26, 41, 45, 50 detects the second set value of the high temperature side temperature.

  As shown in FIGS. 4 (a) and 4 (b), the detected temperature H of each temperature sensor 26, 41, 45, 50 gradually increases with the lapse of the operation time, and the temperature increase determination value R at the position of time T1. To reach. FIG. 4A shows the detected temperature change of the temperature sensors 26, 41, 45, 50 that first reached the temperature rise determination value R among the temperature sensors 26, 41, 45, 50.

  When the detected temperature H reaches the temperature rise determination value R, the controller 55 determines that load suppression is necessary (any one of the cooling water temperature, the lubricating oil temperature, the supply air temperature, and the fuel temperature is equal to or higher than the set value) (S2). : YES) Based on the determination result, the controller 55 controls the engine 1 to reduce the output to a predetermined percentage of AkW (for example, 50% of the rating) (S3 and S4).

  The detected temperature H then increases from the temperature increase determination value R, but gradually decreases due to load suppression, and reaches the temperature increase determination value R again after a predetermined time (position of time T2 in FIG. 4A). When the detected temperature H reaches the temperature rise determination value R again, the controller 55 controls the output to be constant in the AkW state (S5). It is determined whether E minutes (for example, 5 minutes) have elapsed since the latest output arrival (S6). In the first determination, when E minutes have elapsed after the detected temperature H reaches the temperature rise determination value R again (S6: YES), the output of CkW (for example, 10%) is increased (S7 and FIG. 4B). Position at time T3).

  Further, it is determined whether or not the engine generator X has returned to the rated output (S8). If E minutes (5 minutes) have not elapsed since the CkW (10 percent) output was increased, the process returns to S9. When E minutes (5 minutes) have passed since the latest output arrived (S6: YES), the CkW output is further increased (position of time T4 in S7 and FIG. 4B).

  Furthermore, if the output has not returned to the rating (S8: NO), the process returns to S9. Thus, after operating at the same output for E minutes until the output returns to the rated value, the CkW output is returned (position at time T5 in FIG. 4 (b)), and after further operation at the same output for E minutes, the CkW output Is returned (position at time T6 in FIG. 4B), and steps S6 to S9 are repeated to return the output in stages (position at time T7 in FIG. 4B).

  And when an output returns to a rating (S8: YES), load suppression control is stopped and it returns to a normal driving | operation (S10).

  If the detected temperature H has risen above the temperature rise determination value R while the output is being returned, it is determined that load suppression is necessary and the process returns to step S6.

  Further, depending on the driving situation, it may be desired to cancel the load suppression control. In such a case, the load suppression control can be canceled manually. The controller 55 monitors the load suppression release signal (S11). When the release button is pressed, the load suppression control is terminated and the normal operation is resumed (S12). Note that the load suppression control cancel signal is also used when the manual mode is switched or when the controller 55 receives a stop signal of the engine generator X.

  As described above, the engine generator X that has been determined to be a minor failure and whose output has decreased can be disconnected from the other engine generators X. Accordingly, when one engine is under load suppression control while a plurality of engine generators X are in automatic operation, the engine generator X being controlled is disconnected from the system and the output is restored. In this way, the engine generator X that has been overheated due to a minor failure can be preferentially stopped, and a serious failure stop due to the continued high temperature state of the engine 1 can be avoided, and the engine 1 of the engine generator X that has been disconnected is avoided. The power supply can be prioritized within an allowable range that can prevent overheating.

  The present invention is not limited to the embodiment described above. FIG. 7 shows a flowchart of an engine generator according to another embodiment of the present invention. The other present embodiment shown in FIG. 7 avoids a major failure stop due to continuation of a high temperature state of the engine 1 and enables the load suppression control to be performed within a range not exceeding the contract power.

  In facilities such as supermarkets and hospitals, the electric power used is generated by the engine generator X, and the shortage of electric power generated by the engine generator X is purchased from an electric power company. Therefore, the facility contracts with the electric power company using the power obtained by adding the surplus power to the planned purchase power as the contract power. If the power actually supplied from the power company (purchased power) exceeds the contracted power, the facility is charged with a fine in addition to the monthly basic charge and usage fee.

  For example, when a facility that requires 1200 kW of power uses two engine generators X having a rating of 500 kW, the two engine generators X can generate 1000 kW of power. Therefore, it is only necessary to purchase at least a shortage of 200 kW (received power) from the power company. Therefore, the contract power of the electric power company is set to 300 kW in consideration of the surplus power (100 kW). Therefore, if the facility uses purchased power exceeding 300 kW, the power company will be charged a fine.

  In such a facility, if the engine generator X determined to be a minor failure is reduced to 50% of the rated output as in the above embodiment, 500 kW (rated output) is reduced to 250 kW due to the reduced output. To do. As a result, since the power generation capacity of the entire engine generator system is 750 kW (500 kW + 250 kW), it is necessary to purchase a shortage of 450 kW from the power company. As a result, the purchased power (450 kW) exceeds the contract power (300 kW), so the load suppression control is performed in a range where the purchased power does not exceed the contract power.

  Specifically, 300 kW is stored in the controller 55 as contract power. Since the received power at the normal time is 200 kW, there is a margin up to contract power (300 kW) −received power (200 kW) = 100 kW. Therefore, the power to suppress the load is not 100% of the rated output, but (100 kW / 500 kW) × 100 = 20%.

  Therefore, the controller 55 of the present embodiment automatically determines that 20% of the rated output is within a range that does not exceed the contract power (percentage of load suppression), and reduces the output within a range that does not exceed the contract power. Control. Thus, in this embodiment, the output limit value is calculated based on the margin of the received power with respect to the contract power.

  Next, the operation of the engine generator system that performs the load suppression will be described with reference to the flowchart of the engine generator shown in FIG. In addition, the same code | symbol is attached | subjected to the same step process as the flowchart of the engine generator shown in FIG. 5, and each specific description is abbreviate | omitted.

  First, in Steps S1 and S2, if it is determined that load suppression control for reducing the rated power of the engine generator X is necessary, the output is reduced to a load suppression possible percentage (G percent) (S4A). G percent corresponds to 20 percent of the rating, and is a value calculated by the controller 55.

  There is a possibility that an error may occur in the value of the received power used for the calculation of the load suppression possible percentage depending on the measurement time. Therefore, a weighted average processed by the following formula is adopted. That is, the value of the received power is obtained by the equation (p × N + P) ÷ (N + 1). Note that p is the previous weighted average received power, P is the latest received power measured value, and N is the received power weighted average number. By appropriately setting N, the value of the received power subjected to the weighted average process is obtained.

  If E minutes have elapsed after the G percent reduction output is controlled to be constant (S5A) (S6A), the CkW output is increased (S7).

  If the output has not returned to the rating (S8: NO), the process returns to step S9. Thus, until the output returns to the rating, steps S6 to S9 are repeated to return the output stepwise.

  When the engine generator output returns to the rated value (S8: YES), the load suppression is stopped and the normal operation is restored (S10).

  The present invention is not limited to the above embodiment. The temperature monitoring element is not limited to the cooling water temperature, the lubricating oil temperature, the supply air temperature, or the fuel temperature. For example, as shown in FIG. 3 (indicated by phantom lines) and FIG. 8, it is possible to provide a temperature sensor 60 in the generator 56. The generator 56 includes a rotor made of a magnet (not shown) and a stator made of an iron core. The stator is provided with a generator stator temperature sensor 60 such as a thermistor. The generator stator temperature sensor 60 can detect heat generation since a current flows when the generator 56 generates power.

  As shown in FIG. 6, the generator stator temperature sensor 60 detects the temperature at the time of a minor failure (first set value) and the temperature at the time of a major failure (second set value). The generator stator temperature is one of the elements for detecting the load state of the engine 1, and the generator stator temperature sensor 60 detects the load state of the engine 1 by detecting the generator stator temperature. be able to.

  When detecting that at least one of the cooling water temperature, the lubricating oil temperature, the supply air temperature, the fuel temperature, and the generator stator temperature is a set value or more as a temperature monitoring element caused by the engine load The controller 55 controls the output of the engine generator X.

  Further, the controller 55 uses the cooling water temperature, the lubricating oil temperature, the supply air temperature, the fuel temperature, or the generator stator temperature as temperature monitoring elements, or appropriately selects any one as the temperature monitoring element. It is also possible.

1 Engine 2 Lubricating oil system 3 Cooling water system 26 Lubricating oil temperature sensor 41 Cooling water temperature sensor 45 Supply air temperature sensor 50 Fuel thermistor (fuel temperature sensor)
55 Controller (Controller)
58 Operation Control Device 60 Generator Stator Temperature Sensor X Engine Generator

Claims (3)

In an engine having an operation control device that controls an output when it is detected that at least one element of a cooling water temperature, a lubricating oil temperature, a supply air temperature, or a fuel temperature is a set value or more,
When continuously detecting that at least one of the cooling water temperature, lubricating oil temperature, supply air temperature, or fuel temperature is equal to or higher than the set value for a predetermined time, the output is a predetermined value regardless of the detected element. It is limited to the following uniformly, and when it is detected that the temperature of the element that is detected to be equal to or higher than the set value is equal to or lower than the set value in the output limit state, the output before the limit is gradually restored. To engine.   In the engine generator system in which a plurality of engine generators that drive the generator with the engine according to claim 1 are operated in parallel, a generator stator temperature is added as a temperature monitoring element, and the engine generator is disconnected. An engine generator system characterized by preferentially disconnecting engine generators in an output-restricted state.   3. The engine generator system according to claim 2, wherein the engine output limit value is calculated based on a margin of the received power with respect to the contract power, or is set manually.

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