JP5260085B2 - Power generation engine starting device and starting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine starter that prevents the damage and the like of an inverter by suppressing the excessive rise of a generated voltage caused by the excessive revolutions of a generator at the time of starting an engine, especially at a time of hot start, in a power generation device in which a generator is directly driven by an engine and a generated voltage rises proportionally to the revolutions of the generator because no generated voltage regulating function is provided. <P>SOLUTION: The starter comprises the power generation device, which is directly connected to an engine 9 and outputs a generated voltage proportional to the revolutions of the generator 7 without having the generated voltage regulating function, and a start control means 63, which increases an electric load by applying the electric load 19 to the generator 7 so as to regulate the engine revolutions to preset starting-time permissible revolutions or lower when the start of the engine 9 is detected. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  [Technical Field] The present invention relates to an engine starter installed in a so-called cogeneration system that supplies water by driving a generator with an engine and supplies water by using exhaust heat of the engine, and a start method thereof About.

  Recently, a generator is driven by a gas engine that uses city gas as fuel, and the engine is operated at a low output, for example, at an output power rating of about 1 kW, and a hot water supply device is operated using the exhaust heat of the gas engine as a heat source. A household cogeneration device that supplies hot water is known.

As such a household cogeneration device, for example, as disclosed in Patent Document 1, a power storage device and a surplus power consumption heater are provided on the power usage device side, so that the usage amount of the power usage device in the home is small. There is a technique of a cogeneration system in which surplus power of a generator is sometimes stored in power storage means and energized to operate a surplus power consumption heater so that heating for hot water supply can be performed.
Further, a gas engine is shown as an engine that drives a generator of a cogeneration device of Patent Document 1, and gas fuel is supplied to the gas engine at a set flow rate so as to perform a rated operation.

  On the other hand, the gas engine installed in the cogeneration apparatus is started using a recoil starter (manual starter), a cell motor, a motoring of a generator, or the like. And after starting, the engine will self-accelerate, but when stopping the engine during continuous operation and restarting immediately after that, for example, when the protection function is activated by lightning strike, it stops instantaneously and then restarts Since the engine oil is heated to a low friction state, over-rotation may occur when the engine is started by the motoring of the cell motor or the generator.

If the generator has a voltage adjustment function, it is possible to adjust the generated voltage due to overspeed, but it is a small, lightweight, inexpensive generator that does not have a voltage adjustment function for the generator output. In the case of a device, a voltage is generated according to the rotational speed of the magnets that make up the generator. Therefore, a power generation voltage exceeding the withstand voltage of the inverter is generated due to over-rotation, and the inverter is damaged. There is a fear.
For this reason, in a power generator that does not have a voltage adjustment function, it is necessary to perform control that suppresses an excessive increase in the generated voltage due to over-rotation at the time of restarting the engine in a warm state.

As for a gas engine, Patent Document 2 is known as a technique for preventing the occurrence of engine stall or over-rotation when the gas engine is started.
In Patent Document 2, in a gas engine used for a heat pump or the like, the temperature of the gas engine at the time of starting is detected, and the opening of the throttle valve is set based on a preset correspondence relationship. Thus, there is shown a technique for preventing engine stall and overspeed at the start without requiring an idle port for bypassing the throttle valve.
That is, when the gas engine is started, the engine temperature such as the coolant temperature and the lubricating oil temperature is detected, and the opening of the throttle valve is adjusted based on the detected value of the engine temperature. A gas engine that prevents the occurrence of defects is disclosed.

JP 2006-158148 A JP-A-6-288268

  As described above, Patent Document 1 discloses a household cogeneration apparatus, in which a gas engine is provided as an engine for driving a generator of the cogeneration apparatus, and gas fuel is supplied to the gas engine at a set flow rate. Although the engine is rated, the control at the start of the gas engine is not shown. In particular, the excessive generation voltage caused by over-rotation at the start of the engine in a warm state is suppressed. The control to do is not shown.

Further, in Patent Document 2, as described above, the gas engine is limited only to prevent over-rotation by suppressing the throttle opening when the gas engine is started. The technology for preventing over-rotation in combination with the load is not shown, and the control at the time of starting in the gas engine that drives the generator in the cogeneration system is not disclosed.
Further, as disclosed in Patent Document 2, the means for adjusting the throttle valve opening based on the detected value of the engine temperature at the time of starting the gas engine to prevent the engine from over-rotating is disclosed. In an engine where the length of the intake passage to the engine combustion chamber is long and the volume of the intake passage is large, there is a time delay, that is, a time lag, from the adjustment of the throttle valve opening to the decrease in engine rotation. There is a problem of low responsiveness.

  Therefore, the present invention has been made in view of such a background, and the generator is directly driven by the engine, and the generator voltage adjustment function is not mounted, and the generator voltage is proportional to the number of revolutions of the generator. An engine starting device and a starting method for preventing an inverter from being damaged by preventing the generator from over-rotating and generating voltage from rising excessively at the start of the engine, particularly at a warm start The issue is to provide.

In order to solve the above-mentioned problem, a first invention is a starter for a generator engine that drives a generator.
It is directly connected to the engine and has a power generation device that does not have a power generation voltage adjustment function and outputs a power generation voltage in proportion to the rotation of the generator.
Start control means for increasing the power generation load by applying an electric load to the generator so that the engine speed is equal to or less than a preset allowable engine speed at start ;
A hot water supply device is provided that is heated by exhaust heat of the engine, detects engine start by a hot water supply command, and based on a detection signal from an engine oil temperature sensor, the engine is in a warm state when the temperature is equal to or higher than a predetermined temperature. A warm start detection means for determining that
The start control means is actuated when the warm start detection means detects the start in the warm state .

Further, the second invention relates to a method for starting a power generation engine. In the method for starting a power generator engine for driving a power generator, the power generator is directly connected to the engine and is capable of rotating the power generator without having a power generation voltage adjustment function. A power generator that outputs a generated voltage proportionally is provided, a hot water supply device that is heated by the exhaust heat of the engine is provided, engine start is detected by a hot water supply command, and a detection signal from an engine oil temperature sensor On the basis of this, when a temperature state above a predetermined temperature is detected, an electric load is applied to the generator to increase the power generation load so that the engine speed is equal to or less than a preset allowable engine speed at start-up. It is characterized by.

According to the device invention and the method invention, when the engine is warm- started, an electric load is applied to the generator to increase the power generation load so that the engine speed is equal to or less than a preset allowable engine speed at startup. As a result, the engine is prevented from over-rotation, the power generation voltage of the generator is prevented from rising above a certain value, the power generation exceeding the withstand voltage of the inverter is prevented, and the inverter or the like is prevented from being damaged.

Further , according to the device invention and the method invention , a hot water supply device heated by the exhaust heat of the engine is provided, engine start is detected by a hot water supply command, and based on a detection signal from an engine oil temperature sensor, When a temperature state above a predetermined temperature is detected, an electric load is added to the generator to increase the power generation load so that the engine speed is equal to or less than a preset allowable engine speed at startup. At the time of start-up, the engine oil is at a high temperature and is in a low friction state, so over-rotation is likely to occur, but over-rotation can be suppressed by applying an electric load.

  In the apparatus invention, preferably, the electrical load of the start control means is energized to the surplus power heater. According to such a configuration, the power generation output is consumed by energizing the surplus power heater, thereby Over-rotation can be prevented. If the number of revolutions increases, the heater is turned on, and if the number of revolutions falls, the heater is turned off, so that the number of revolutions can be controlled and the number of revolutions of the engine can be controlled.

Furthermore, in addition to the exhaust heat, the surplus power heater is installed as a hot water supply heating source of the water heater, and it is preferable to energize the surplus power heater when the electric load is turned on. As a result, the thermal efficiency of the cogeneration system that supplies power and hot water can be increased.

  In the device invention, preferably, the input of the electric load is controlled by the generator output voltage, that is, the generator output voltage is detected without directly detecting the engine speed or the generator speed. Thus, the increase or decrease of the engine or generator speed is determined, and the supply to the surplus power heater is controlled. According to such a configuration, an excessively high power generation voltage state is detected directly, and the surplus power heater is turned on when the detected voltage value is equal to or higher than the threshold voltage, so the power generation voltage of the generator also rises above a certain value. Therefore, it is possible to reliably obtain the effect of preventing breakage below the withstand voltage of the inverter.

  Preferably, in the device invention, the electrical load is turned on when the generator output voltage is equal to or higher than a threshold voltage, and the threshold is increased with time. Also, when the generator output voltage is equal to or higher than the threshold voltage. The electrical load may be turned on and the electrical load may be reduced with time after the electrical load is turned on.

According to such a configuration, by increasing the threshold value with time, it is possible to prevent the engine from continuing to be applied with brake torque and to increase the engine speed, thereby enabling a stable start.
Similarly, if the electric load continues to be turned on, the brake torque continues to be applied to the engine, so the engine speed does not increase. To prevent this, the load on the surplus power heater is gradually reduced with time. Stable start is possible.

  Preferably, in the device invention, the start control means includes an engine control means for controlling an output of the engine, and the intake air throttle is controlled by the engine control means when the engine start means exceeds an allowable engine speed after the electric load is applied. It may be throttled or the fuel supplied to the engine may be limited.

  According to such a configuration, when the engine speed exceeds the allowable engine speed at start-up even when an electric load is applied, the engine output is directly controlled by reducing the engine output or by restricting the fuel supply. Therefore, the power generation voltage of the generator can be prevented from rising above a certain value, and the effect of preventing breakage can be reliably obtained by making it lower than the withstand voltage of the inverter.

  According to the present invention, in the power generator in which the generator is directly driven by the engine and the voltage adjustment function is not mounted and the generated voltage rises in proportion to the rotational speed of the generator, the temperature is particularly high when the engine is started. It is possible to obtain an engine starter and a start method that prevent the inverter from being damaged by preventing the generator from over-rotating at the start of the state and causing the generated voltage to rise excessively.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Only.

The drawings referred to in the description of the embodiment are as follows.
FIG. 1 is an explanatory diagram showing a schematic configuration of a household cogeneration apparatus to which the present invention is applied, FIG. 2 is a block configuration diagram of a power supply unit (power generation apparatus) of the cogeneration apparatus, and FIG. 3 is a gas engine. FIG. 4 is a control block diagram showing the starting control means, and FIG. 5 is a time variation of the engine speed and the power generation output (engine load) at the time of starting the engine in the first embodiment. FIG. 6 is a chart showing temporal changes in engine speed and power generation output (engine load) at the time of engine start in the second embodiment.

With reference to FIG. 1, the outline | summary of the domestic cogeneration apparatus 1 to which this invention is applied is demonstrated.
The cogeneration apparatus 1 includes a power supply unit 3 that generates power and a hot water supply unit 5 that supplies hot water.
The power supply unit 3 is provided with a gas engine 9 that drives a generator 7 so that the power generated by the generator 7 has the same voltage and frequency as those of a commercial system that is an external power source by an inverter 11 for grid connection. Are sent to the power usage device in the home through the switchboard by the feeder 13. Further, the gas engine 9 is operated at a rated power output of about 1 kW during operation, and is set so that vibration noise is minimized during this rated operation.

  The hot water supply section 5 is provided with a cooling water pipe 15 through which the engine cooling water for utilizing the exhaust heat of the gas engine 9 flows through the gas engine 9, and also from the exhaust heat exchanger 17. Heat is given to the cooling water in 15, and heat is also given to the cooling water by the surplus power heater 19.

  The heated cooling water warms water stored in the hot water storage tank 25 by the heat exchangers 21 and 23 or water supplied to a heating terminal for indoor heating provided in the home (not shown). Similarly, the heat exchangers 27 and 29 are heat exchangers for supplying hot water in the home, and an auxiliary heat source device 31 is provided when the heat source is insufficient.

Next, the detailed block block diagram of the electric power feeding part 3 which performs the electric power generation of the cogeneration apparatus 1 in FIG. 2 is shown. Components identical to those in FIG.
A generator 7 is provided directly connected to the gas engine 9. This generator 7 is an AC generator and has a built-in permanent magnet to generate an induced voltage proportional to the rotational speed.
The inverter board 35 has the same voltage and frequency as the AC / DC converter 37 that converts the alternating current of, for example, 250 V and 213 Hz to the direct current of about 350 V generated by the generator 7 and the commercial system 39 that uses the direct current 350 V as an external power source. A DC / AC inverter 41 for converting to 100V / 200V alternating current and a circuit for confirming the state of power flow from the switchboard 45 to the commercial system based on the current value from the current sensor 43 are mounted. In addition, power is supplied from the switchboard 45 to the power usage apparatus 47 in the home.

  The power supply unit 3 is configured by the gas engine 9, the generator 7, the inverter board 35, and the ECU board 49. Note that the AC / DC converter 37 and the DC / AC inverter 41 are such that the commercial system 39, which is an external power source, has little fluctuations in frequency and voltage, whereas the power generated by the generator 7 depends on the usage state of the power. Since the voltage is likely to fluctuate, the voltage and frequency of electricity generated by the generator 7 are provided so as to be equal to those of the commercial system 39 that is an external power source.

  The ECU board 49 is mounted with a CPU 51 that performs electronic control such as a throttle, a gas electromagnetic valve, an ignition device, and various sensors, and controls the operation of the gas engine 9. In addition, a control power supply 55 that supplies power to the ECU board 49 and the inverter board 35 is mounted on the inverter board 35.

  Further, the inverter board 35 controls the AC / DC converter 37 and the DC / AC inverter 41, and the power consumption of the surplus power heater 19 provided outside the inverter board 35 is duty controlled by PWM (Pulse Width Modulation) control. A CPU 53 is provided to send an instruction to the semiconductor switch 59 for controlling the (Duty) ratio.

  Normally, in such a cogeneration apparatus 1, a switch 61 such as a breaker or a relay is provided when electricity flows through the commercial system 39 at the time of a power failure. The power is cut off.

  A current sensor 43 is provided between the commercial system 39 serving as an external power source and the switchboard 45, and the power used by the commercial system 39 is detected. Since the output of the generator 7 is constant at 1 KW, for example, as described above, when the power used by the power usage apparatus 47 in the home exceeds 1 KW, power is supplied from the commercial system 39 via the switchboard 45.

  On the contrary, if the power consumption of the power usage device 47 in the home is less than 1 KW, the surplus electricity flows backward to the commercial system 39 as it is. In order to prevent this, the measurement result of the current sensor 43 provided between the commercial system 39 and the switchboard 45 is constantly sent to the CPU 53 mounted on the inverter board 35, and the CPU 53 determines that the commercial system 39 from the sent measurement result. If a decrease in the current flowing from the power supply to the switchboard 45 is detected, a reverse power flow may occur, and PWM control is performed so that power corresponding to the surplus power is consumed by the semiconductor switch 59 that controls the power used by the surplus power heater 19. A signal is sent.

The CPU 51 provided on the ECU board 49 and the CPU 53 provided on the inverter board 35 constitute a start control means 63 of the present invention.
Next, the start control means 63 will be described with reference to FIG. 3, FIG. 4, and FIG. The start control means 63 is roughly composed of an engine control means 65 for controlling the gas engine 9 and an electric load control means 67 for controlling the power generation load of the generator 7.

FIG. 3 shows an overall configuration diagram of the start control means 63 according to the present invention. The same components as those in FIGS.
In FIG. 3, a gas engine 9 is a single-cylinder or multi-cylinder four-cycle gas engine, a piston 72 fitted in a cylinder 70 so as to be freely slidable, and a crankshaft for converting the reciprocating motion of the piston 72 into rotation. 74, a combustion chamber 76 defined between the upper surface of the piston 72 and the inner surface of the cylinder 70, an intake port 78 connected to the combustion chamber 76, an intake valve 80 for opening and closing the intake port 78, and the combustion chamber An exhaust port 82 connected to 76, an exhaust valve 84 for opening and closing the exhaust port 82, and the like.

In the middle of the intake port 78, a gas mixer 86 and a throttle valve 88 are installed. The fuel gas supplied from the fuel gas pipe 90 through the gas amount adjusting valve 92 and the newly taken air from the outside are supplied by the gas mixer 86. Mix.
The flow rate of the air-fuel mixture is adjusted by opening control of the throttle valve 88, and the air-fuel mixture is supplied to the combustion chamber 76 by opening the intake valve 80.
In this example, the ignition device 94 burns the air-fuel mixture in the combustion chamber with sparks generated by the ignition plug, and is composed of an ignition plug and an ignition coil.
The gas engine 9 having such a configuration drives the generator 7 directly connected to the crankshaft 74 thereof.

  In FIG. 3, the start control means 63 includes an engine speed detection value from the engine speed detector 96 to the detected value of the engine speed in the gas engine 9, an electric load from the load detector 98, that is, a detected value of the engine load applied to the gas engine 9, and the oil temperature. The detection value of the lubricating oil temperature of the gas engine 9 is input from the sensor 100, and the detection value of the environmental state such as atmospheric pressure, atmospheric temperature, air humidity and the like related to the operation of the gas engine 9 is input from the environmental state sensor 102, respectively. Yes. Further, the generated voltage value is input from the voltage detector 104 of the generator 7. The engine speed detector 96 may be detected from the generated AC frequency of the generator 7 or from the rotation of the engine output shaft.

  The engine control means 65 in the start control means 63 outputs the opening degree signal of the throttle valve 88 and the opening degree signal of the gas amount adjusting valve 92 based on the detected values. In addition, the electrical load control means 67 in the start control means 63 sets the energization timing and duty ratio to the surplus power heater 19 to the semiconductor switch 59 that controls the power consumption of the surplus power heater 19 that is the electrical load of the generator 7. Instruct. Further, the start control means 63 also controls motoring by the start inverter (AC / DC converter 37) for the generator 7.

Next, FIG. 4 shows a control block diagram of the start control means 63, and the start control means 63 will be described with reference to FIG.
In the starting rotational speed / load setting unit 110 of the starting control means 63, an allowable starting rotational speed that is an allowable maximum engine rotational speed at the time of starting the engine, that is, an overspeed determination rotational speed Na shown in FIG. 5 is set. . Further, in the starting rotational speed / load setting unit 110, a power consumption value (power generation load value) D of the surplus power heater 19 to be input as an electric load at the time of starting the engine is set. Further, a heater ON threshold rotation speed Nb for starting energization to the surplus power heater 19 is set.

When the engine is started, as shown in the chart of FIG. 5 showing the time change of the engine speed and power generation output (engine load) at the time of engine start, the engine speed is As shown by the Z line in the figure, after starting, the engine speed increases to a constant no-load rotation speed (idle rotation speed) N1 in a no-load state, and after driving at this idle rotation speed N1, the load (generated power) with increasing the load on the power, raised the engine speed up to the rated speed N ₀ increases the opening degree of the throttle valve, for continuous operation in the constant rated rotational speed N _0.

  When the gas engine 9 is in a warm state like the restart when the time interval after the engine stop is short, the engine oil temperature is at a temperature level close to that during operation. As shown by the S line, the engine speed tends to increase beyond the over-rotation determination speed (allowable speed at start) Na in the no-load state.

(First embodiment)
The engine 9 is started by the hot water supply command. First, based on the detection signal from the oil temperature sensor 100, for example, when the engine oil temperature is 50 ° C. or higher, it is determined that the engine 9 is in the warm state.
Then, the start inverter (AC / DC converter 37) of the generator 7 is operated by the CPU 53 (electric load control means 67), the generator 7 is motored, and the engine 9 is started. Note that the hot start command detecting means and the oil temperature sensor 100 constitute a warm start detecting means.

  Thereafter, when the engine speed is input from the engine speed detector 96 to the start speed / load control unit 112 of the start control means 63, the start speed / load control unit 112 determines the engine speed. The detected value is compared with the over-rotation judgment rotational speed shown in FIG. 5 set in the starting rotational speed / load setting unit 110, that is, the allowable starting rotational speed Na and the heater ON threshold rotational speed Nb. When the detected value reaches the heater ON threshold rotation speed Nb (t1), the surplus power heater 19 is energized and an electric load is applied from this point (point A in FIG. 5).

  Thereafter, even if surplus power is input, the rotational speed further increases, and when the allowable rotational speed Na at the start is reached (point E in FIG. 5), the rotational speed / load control unit 112 at the start A control operation signal for reducing the opening degree is sent to the throttle valve 88 to reduce the flow rate of the air-fuel mixture to a constant flow rate, and a control operation signal is sent to the gas amount adjusting valve 92 to reduce the fuel gas flow rate to reduce the engine output. .

In addition, the engine speed, that is, the electric load (the surplus electric power heater 19) is held in the engine speed setting / load control unit 112, which is set in the engine speed / load control unit 112 at the time of starting. D line in FIG. 5). As a result, the engine speed decreases from B in FIG. 5 to the rated speed N _{0 of} C.
After the above starting control (t2), normal engine control is entered, and the engine 9 and generator are controlled by controlling the engine load, that is, the electric load (the surplus power heater 19), the throttle valve 88, and the gas amount adjusting valve 92. 7 is operated at a rated speed N ₀ and a rated load G.

  According to such an embodiment, it is possible to prevent over-rotation of the generator 7 at the time of engine warm start by using the surplus power heater 19 provided to prevent a reverse power flow to the commercial system 39. it can.

  Further, when the heater ON threshold rotation speed Nb of the energization start timing to the surplus power heater 19 is exceeded, first, the surplus power heater 19 is energized and a load is applied to the generator 7 to increase the rotation rate of the generator 7. However, if the engine speed still reaches the over-rotation determination speed (allowable speed at start) Na, a control signal for reducing the opening of the throttle valve 88 is sent to the throttle valve 88 to reduce the flow rate of the air-fuel mixture to a constant flow rate. At the same time, a control operation signal is sent to the gas amount adjusting valve 92 so as to reduce the fuel gas flow rate.

  For this reason, as in the prior art, the means for adjusting the throttle valve opening based on the detected value of the engine temperature at the time of starting the gas engine (throttle) to prevent the engine from over-rotation is used. In an engine with a long intake passage to the combustion chamber and a large intake passage volume, there is a time lag or time lag from adjusting the throttle valve opening to lowering the engine speed. In this embodiment, as described above, after the engine speed reaches the allowable start speed at the start, as described above, first, after applying the load of the surplus power heater 19 to the engine, Since control is performed to reduce the opening of the throttle valve 88, there is no time lag due to the length and volume of the intake passage as in the prior art, and it is possible to start up at the time of starting. That rotation increase responsiveness is higher suppression, engine overspeed inhibiting effect becomes higher at the start.

(Second Embodiment)
Next, a second embodiment will be described.
Based on the detection signal from the oil temperature sensor 100, for example, when the temperature of the engine oil is 50 ° C. or higher, it is determined that the engine 9 is in the warm state, and the CPU 53 (electric load control means) 67), the starting inverter of the generator 7 is operated, and the generator 7 is motored to start the engine 9.
An ON signal is output to the semiconductor switch 59 so as to start energization of the surplus power heater 19 by the engine speed / load control unit 112 immediately after the start of the engine.

Thereafter, when the heater 9 reaches the heater ON threshold change start rotational speed Nc while the electric load (the surplus power heater 19) operates while the engine 9 is accelerated, the heater ON to the surplus power heater 19 is thereafter performed by the heater ON threshold rotational speed Nb. The heater ON threshold rotation speed Nb is increased step by step at regular intervals. The heater ON threshold rotation speed Nb may be continuously increased instead of the control for increasing the ON threshold rotation speed Nb in steps at regular intervals.
The heater ON threshold change start rotation speed Nc is set to a rotation speed at which the generated current value from the generator 7 starts to generate power exceeding the current value for motoring that flows from the startup inverter to the generator 7 at the start. By doing so, motoring can be reliably performed until the start of power generation, and thereafter the engine speed can be increased smoothly.

  That is, the heater ON threshold rotation speed Nb is increased stepwise at regular intervals, the ON timing of the surplus power heater 19 is set to a speed higher than the actual increase in engine speed, and the surplus power heater is set. The ON operation rate of 19 is reduced to reduce the electric load, and the engine speed is gradually increased. By increasing the heater ON threshold rotation speed Nb in steps at regular intervals, the load on the generator can be reduced in steps as shown in FIG. It should be noted that the heater ON threshold rotation speed Nb may be increased continuously instead of being increased stepwise at regular intervals.

Instead of the control for increasing the heater ON threshold rotation speed Nb with time, the power consumption itself of the surplus power heater 19 is decreased with time, thereby reducing the ON operation rate of the surplus power heater 19 and increasing the electric load. May be decreased to gradually increase the engine speed.
The control for reducing the power consumption itself of the surplus power heater 19 with time is performed by the control for reducing the ON duty ratio of energization by the semiconductor switch 59 that controls energization to the surplus power heater 19.

As described above, the increase in the rotational speed is suppressed by turning on the surplus electric power heater 19, but if the energization is continued for a long time, the engine speed-up is hindered, so the heater ON threshold rotational speed Nb is increased with time. Alternatively, by reducing the power consumption of the surplus power heater 19, the electric load can be reduced and the engine speed can be gradually increased.
Since it is possible to control to increase the number of revolutions, the engine 9 is started in the warm state, and at the same time, the surplus power heater 19 is turned on, and then the ON and OFF control is repeated, whereby the engine 9 can be controlled to increase / decrease, so that it is possible to quickly shift to the rated rotation speed N ₀ in a short time compared to the control in which the surplus power heater 19 with constant power consumption is turned on as in the first embodiment. It becomes like this.

(Third embodiment)
Next, a modified example of timing for turning on the surplus power heater 19 will be described as a third embodiment.
In the vicinity of the oil temperature threshold, there are those that over-rotate and those that do not over-rotate due to individual differences in the engine. In order to prevent this, the surplus electric power heater 19 is simply turned on when the overspeed determination speed Na is exceeded.

  When the rotational speed further increases beyond the over-rotation determination rotational speed Na, the load of the surplus power heater 19 is further charged to the generator 7 in accordance with the degree of over-rotation to suppress the increase in rotation.

(Fourth embodiment)
In the first, second, and third embodiments, the surplus power heater 19 is controlled to be turned on and off by the rotational speed of the gas engine 9, that is, the rotational speed signal of the generator 7, but in the fourth embodiment, the rotational speed is controlled. Instead, the generated voltage generated from the generator 7 may be directly detected and controlled by the voltage detector 104.
That is, the heater ON threshold voltage value Vb may be set in advance, and when the output voltage of the generator 7 reaches the heater ON threshold voltage value Vb, energization of the surplus power heater 19 may be started. Thereafter, the heater ON threshold voltage value Vb may be controlled to be increased, for example, in increments of 10 V every 1 to 7 seconds. As with the setting of the rotation speed Nc, the heater ON threshold change start voltage value Vc is such that the generated current value from the generator 7 exceeds the current value for motoring that flows from the startup inverter to the generator 7 at the start. Is the voltage value at which.

なお、ＶｕはＵ相系統電圧（Ｖ）であり、ＶｖはＶ相系統電圧（Ｖ）である。そして、ヒータ電圧閾値範囲を３２０〜４１０（Ｖ）の範囲に設定している。 Specifically, the heater ON threshold voltage value Vb is calculated and set according to the following equation (1) as an example of control based on the voltage as described above.

Vu is the U-phase system voltage (V), and Vv is the V-phase system voltage (V). And the heater voltage threshold value range is set to the range of 320-410 (V).

Heater ON threshold rotation speed Nb, over-rotation judgment rotation speed (allowable rotation speed at start-up) Na
The heater ON threshold voltage value Vb and the over-rotation determination voltage value (starting allowable voltage value) Va corresponding to are calculated in advance and set in the starting rotation speed / load setting unit 110.

  According to this embodiment, since the excessive rise state of the generated voltage is directly detected and controlled from the generated voltage that is the output of the generator, it is possible to reliably prevent the generator from over-rotating when the engine is warm.

(Fifth embodiment)
In the fifth embodiment, over-rotation determination rotational speed (permissible rotational speed at start-up) Na, over-rotation determination is made according to environmental conditions related to engine operation, such as atmospheric pressure, atmospheric temperature, air humidity, and engine lubricating oil temperature. Learning correction is performed for the voltage value (allowable voltage value at start-up) Va, the heater ON threshold rotation speed Nb, the heater ON threshold voltage value Vb, the set power consumption value (duty ratio) of the surplus power heater 19, and the like. Start.

  In the control block diagram of FIG. 4, the detected value of the lubricating oil temperature at the outlet of the engine 9 from the oil temperature sensor 100, the atmospheric pressure, the atmospheric temperature, the air humidity, etc. related to the operation of the engine 9 from the environmental state sensor 102. The detected value of the environmental state is input to the starting rotation speed / load control unit 112 of the starting control means 63, respectively.

Further, in the starting condition storage unit 114 of FIG. 4, environmental state data such as atmospheric pressure, atmospheric temperature, and air humidity related to the operation of the engine from the environmental state sensor 102 input as described above is stored in the engine. It is accumulated in association with the actual driving performance.
Further, in the start condition storage unit 114, the environmental state, the allowable start rotation speed Na, the start allowable voltage value Va, the heater ON threshold rotation speed Nb, the heater ON threshold voltage value Vb, and the consumption of the surplus power heater 19 are stored. The relationship between the power value (duty ratio) and the correction value is set.
Further, the detection data of the engine oil temperature at the outlet of the engine 9 input from the oil temperature sensor 100 is accumulated in the starting condition storage unit 114 in association with the operation results of the engine and the like. The relationship between the correction value with the allowable rotation speed Na at the start, the allowable voltage value Va at the start, the heater ON threshold rotation speed Nb, the heater ON threshold voltage value Vb, and the power consumption value (duty ratio) of the surplus power heater 19 is set. ing.

  In the starting rotation speed / load control unit 112, the environmental state detection value from the environmental state sensor 102 and the detected value of the lubricating oil temperature from the oil temperature sensor 100 are accumulated in the starting condition storage unit 114. Comparing the accumulated data of the environmental condition and the accumulated data of the lubricating oil temperature, the correction calculation of the following condition setting is performed.

For example, when the detected value of the ambient temperature among the detected environmental state values is higher than the average value of the ambient temperature data accumulated in the start condition storage unit 114, an overspeed is likely to occur when the ambient temperature rises. Allowable starting rotation speed Na (Va) and heater ON threshold rotation speed Nb (Vb) are set to a rotation speed lower than the set values in the first to fourth embodiments, and consumption of surplus power heater 19 is performed as necessary. Increase the power value (duty ratio).
When the detected value of the atmospheric temperature is lower than the average value of the atmospheric temperature data, the allowable rotational speed Na (Va) at the start, the heater ON threshold rotational speed Nb (Vb), and the consumption of the surplus power heater 19 The power value (duty ratio) need not be corrected.
In other words, when it is low, the problem is that the problem of overspeed is unlikely to occur because the friction of the lubricating oil increases.

Further, for example, when the detected value of the lubricating oil temperature is higher than the average value of the lubricating oil temperature data accumulated in the starting condition storage unit 114, an overspeed is likely to occur when the lubricating oil temperature rises. Allowable starting rotation speed Na (Va) and heater ON threshold rotation speed Nb (Vb) are set to a rotation speed lower than the set values in the first to fourth embodiments, and consumption of surplus power heater 19 is performed as necessary. Increase the power value (duty ratio).
When the detected value of the lubricating oil temperature is lower than the average value of the lubricating oil temperature data, the allowable starting rotational speed Na (Va), the heater ON threshold rotational speed Nb (Vb), and the surplus power heater 19 The power consumption value (duty ratio) may not be corrected.
In other words, when it is low, the problem is that the problem of overspeed is unlikely to occur because the friction of the lubricating oil increases.

  According to the fifth embodiment described above, the environmental conditions related to the operation of the engine 9, such as atmospheric pressure, atmospheric temperature, and air humidity, the lubricating oil temperature of the engine 9, the allowable rotational speed Na (Va) at the start, and the heater The relationship between the ON threshold rotation speed Nb (Vb) and the power consumption value (duty ratio) of the surplus power heater 19 is acquired and stored in association with the operation results of the engine (9), and the stored data is stored. When the engine 9 is warm-started, the engine speed and the engine load are set to the allowable start speed Na (Va), the heater ON threshold speed Nb (Vb), and the power consumption value (duty ratio) of the surplus power heater 19. ) Is effectively controlled to avoid over-rotation when the engine 9 is started. It can be set accurately by the learning effect using the accumulated data, and it is possible to avoid the occurrence of variations in startability due to variations in the environmental conditions and engine lubricating oil temperature and the occurrence of dangerous starting.

  According to the present invention, in the power generator in which the generator is directly driven by the engine and the voltage adjustment function is not mounted and the generated voltage rises in proportion to the rotational speed of the generator, the temperature is particularly high when the engine is started. It is possible to obtain an engine starting device and a starting method for preventing the inverter from being damaged by preventing the generator from over-rotating at the time of starting the state and preventing the inverter from being damaged. This is useful when applied to a driving engine starter.

It is explanatory drawing which shows schematic structure of the domestic cogeneration apparatus to which this invention is applied. It is a block block diagram of the electric power feeding part of a cogeneration apparatus. It is explanatory drawing which shows the whole structure of a gas engine. It is a control block diagram which shows a starting control means. It is a chart figure which shows the time change of the engine speed at the time of engine starting in a 1st embodiment, and power generation output (engine load). It is a chart figure which shows the time change of the engine speed at the time of engine starting in a 2nd embodiment, and power generation output (engine load).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cogeneration apparatus 3 Electric power feeding part 5 Hot water supply part 7 Generator 9 Gas engine (engine)
DESCRIPTION OF SYMBOLS 11 Inverter 19 Surplus electric power heater 59 Semiconductor switch 63 Start-up control means 65 Engine control means 67 Electric load control means 88 Throttle valve 92 Gas amount adjustment valve 96 Engine speed detector 98 Load detector 100 Oil temperature sensor 102 Environmental condition sensor 104 Voltage Detector 110 Start speed / load setting section 112 Start speed / load control section 114 Start condition storage section Na Over-rotation judgment speed (allowable speed at start-up)
Nb Heater ON threshold rotation speed Va Over-rotation judgment voltage value (allowable voltage value at start)
Vb Heater ON threshold voltage value

Claims (9)

In the starting device for the generator engine that drives the generator,
It is directly connected to the engine and has a power generation device that does not have a power generation voltage adjustment function and outputs a power generation voltage in proportion to the rotation of the generator.
Start control means for increasing the power generation load by applying an electric load to the generator so that the engine speed is equal to or less than a preset allowable engine speed at start ;
A hot water supply device is provided that is heated by exhaust heat of the engine, detects engine start by a hot water supply command, and based on a detection signal from an engine oil temperature sensor, the engine is in a warm state when the temperature is equal to or higher than a predetermined temperature. A warm start detection means for determining that
A starter for a power generation engine , wherein the start control means is operated when the warm start detection means detects a start in a warm state . 2. The starter for a power generation engine according to claim 1, wherein the electric load of the start control means is energization of a surplus power heater . The starter for a power generation engine according to claim 2, wherein the surplus power heater is installed in addition to the exhaust heat as a hot water supply heating source of the hot water supply apparatus, and the surplus power heater is energized when the electric load is turned on. . 3. The starting device for a power generation engine according to claim 1, wherein the electric load is controlled by the generator output voltage . 5. The starter for a power generation engine according to claim 4, wherein when the generator output voltage is equal to or higher than a threshold voltage, the electric load is turned on and the threshold is increased with time . 5. The starter for a power generation engine according to claim 4, wherein the electric load is turned on when the generator output voltage is equal to or higher than a threshold voltage, and the electric load is reduced with time after the electric load is turned on . The start control means includes engine control means for controlling an output of an engine, and the intake air throttle is throttled by the engine control means when the start-up allowable rotational speed is exceeded after the electric load is applied. The starter for a power generation engine according to 1 . The start control means has engine control means for controlling engine output, and the engine control means limits fuel supplied to the engine when the start allowable rotation speed is exceeded after the electric load is applied. The power generation engine starter according to claim 1 . In the starting method of the generator engine for driving the generator,
A power generation device is provided that is directly connected to the engine and that does not have a power generation voltage adjustment function and outputs a power generation voltage in proportion to the rotation of the generator.
When a hot water supply device that is heated by the exhaust heat of the engine is provided, the start of the engine is detected by a hot water supply command, and based on the detection signal from the engine oil temperature sensor, a temperature state of a predetermined temperature or more is detected,
A method for starting a power generation engine, comprising: adding an electric load to the generator to increase the power generation load so that the engine speed is equal to or less than a preset allowable start speed .

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