JP2004108355A - Control device for engine-driven generating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an engine-driven generating device capable of restraining variation of an output voltage of a generator at rapid change of a load. <P>SOLUTION: A control system is provided for controlling a throttle valve 2 so as to compensate variation of the output voltage accompanied by variation of the load of the generator 3. Further, a load rapid increase time injection control means is provided for controlling a fuel injection device so that an air-fuel ratio of a mixture supplied to an engine 1 when the output voltage of the generator is lowered by rapid increase of the load is varied from the lean side to the rich side, and a load rapid decrease time injection control means is provided for controlling the fuel injection device so as to shut off the fuel when the output voltage is raised by rapid decrease of the load. The output of the engine 1 is varied before the output of the engine is adjusted by control of the throttle valve at rapid change of the load, and thereby variation of the output voltage of the generator 3 is restrained. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for controlling an engine-driven power generator.
[0002]
[Prior art]
As an engine-driven power generator, a so-called inverter power generator is often used in which an output of an AC generator driven by an engine is temporarily converted to a DC output, and then converted to an AC voltage having a certain frequency by an inverter. I have.
[0003]
This type of power generator includes an engine, an AC generator driven by the engine, a DC converter for converting the output of the generator into a DC output, and an AC output of a constant frequency that outputs the DC converter. And an inverter that converts the data into a signal.
[0004]
The control device that controls this type of power generator includes an engine throttle required to maintain the output voltage of the generator at a target value (a target value required to generate an AC output of a magnitude set from the inverter). An operation amount calculating means for calculating an operation amount of the valve, and an actuator driving means for applying a drive current to an actuator for operating the throttle valve so as to operate the throttle valve by the calculated operation amount, are provided. The throttle valve of the engine is controlled to keep the output voltage of the generator at a target value in response to the fluctuation.
[0005]
FIG. 7 shows the configuration of a conventional control device of this type. In FIG. 1, reference numeral 1 denotes an engine having a throttle valve 2, and 3 denotes an AC generator such as a magnet type AC generator having a rotor mounted on a crankshaft of the engine. Reference numeral 4 denotes a DC converter for converting the AC output of the generator 3 into a DC output, and reference numeral 5 denotes an inverter for converting the output of the DC converter 4 into an AC voltage having a commercial frequency. The DC converter 4 includes a rectifier. The inverter 5 includes a bridge-type switch circuit in which switch elements such as FETs are connected in a bridge, and a filter that removes a harmonic component from an AC voltage output from the switch circuit. And a circuit.
[0006]
In order to operate the throttle valve 2, an output shaft of an electric actuator 6 driven by a motor or the like is connected to an operation shaft of the throttle valve 2.
[0007]
Reference numeral 7 denotes a control device, which is required for outputting a voltage detection value Er corresponding to the output voltage of the generator detected from the output side of the DC power supply unit 4 to the inverter 5 to output a rated output voltage. A deviation calculator 7A that calculates a deviation between the voltage detection value and the target value in comparison with the target value Et, and performs a proportional / integral / differential calculation (PID calculation) on the deviation calculated by the deviation calculator 7A. An operation amount calculation unit 7B for calculating the operation amount of the throttle valve 2 required to reduce the deviation to zero, and a drive current required for operating the throttle valve 2 by the operation amount calculated by the calculation unit 7B is supplied to the actuator 6. A throttle control unit 7C for generating a control signal for giving an instruction to apply the control signal; and a throttle drive unit 7D for supplying a drive current to the actuator 6 in accordance with the control signal supplied from the control unit 7C. There.
[0008]
The control device 7 includes, in addition to these elements, an ignition timing control unit that controls the ignition timing of the engine, a fuel injection control unit that controls a fuel injection device that supplies fuel to the engine, and an AC voltage of the commercial frequency from the inverter 5. Inverter control means for controlling a switch element constituting the inverter so as to output the signal is provided, but these are not shown.
[0009]
In the engine-driven power generator shown in FIG. 7, the DC voltage obtained by converting the output voltage of the generator 3 by the DC converter 4 is converted into an AC voltage of a commercial frequency by the inverter 5 and supplied to the load. The controller 7 uses the output voltage of the generator detected through the DC converter 4 as a control amount, and supplies a drive current to the actuator 6 so as to maintain the output voltage at a target value, thereby controlling the throttle valve opening. As a result, the output of the engine is controlled to keep the output voltage of the inverter 5 at the rated value.
[0010]
[Problems to be solved by the invention]
In the control device shown in FIG. 7, the output of the generator is adjusted only by controlling the throttle valve. When such control is performed, the change in load immediately appears as a change in the output voltage of the generator, but after the output voltage of the generator changes, the throttle valve actually moves to adjust the output of the engine. Because there is a considerable delay before the load changes, the fluctuation range of the output voltage of the generator when a steep load change occurs becomes large, and when the load increases suddenly, the output voltage of the generator drops greatly and the load operates. Could be adversely affected.
[0011]
Also, when the load suddenly decreases, the output voltage of the generator rises greatly and a high voltage may be applied to the elements constituting the inverter. Therefore, it is necessary to use an expensive element having a high withstand voltage as the element constituting the inverter. There was a problem.
[0012]
In the above example, the output voltage of the generator is set as the control amount, and the control is performed so as to keep the output voltage of the generator at the target value with respect to the load fluctuation of the generator. When the output of the engine is controlled so that the control amount is kept at a target value with respect to the fluctuation, or when another parameter that reflects the load fluctuation, for example, the rotation speed of the generator is used as the control amount, the generator A similar problem occurs when the rotation speed of the generator is controlled to be constant so as to keep the output frequency of the generator constant.
[0013]
An object of the present invention is to provide an engine-driven power generator that controls the output of an engine such that a parameter indicating a change when the load of the generator fluctuates is used as a control amount and the control amount is maintained at a target value with respect to the load fluctuation. In a control device, an output of an engine is immediately adjusted when a load shows a steep change to prevent a large fluctuation in a control amount.
[0014]
[Means for Solving the Problems]
The present invention relates to an engine-driven power generator including an engine that is supplied with fuel by a fuel injection device and ignited by an ignition device, and an AC generator that is driven by the engine. The present invention is directed to a control device of an engine-driven power generator that controls an output of an engine such that a parameter indicating a change is set as a control amount and the control amount is maintained at a target value with respect to a change in load.
[0015]
Here, the parameter indicating the change when the load of the generator fluctuates includes the output voltage and the rotation speed of the generator. Further, in the case of an inverter power generator that converts the output of the generator into a DC output by a DC converter and then converts the DC output into an AC output of a commercial frequency by an inverter, the output voltage of the DC converter is used as a control amount. Is also good.
[0016]
In the present invention, an actuator for operating a throttle valve of an engine, a control amount detected as a control amount detection value that reflects a value of the control amount, and a control target set for the control amount detection value and the control amount. A deviation calculating means for calculating a deviation from the value, an operation amount calculating means for calculating an operation amount of the throttle valve required to make the deviation calculated by the deviation calculating means zero, and a throttle for the calculated operation amount. Actuator driving means for driving the actuator to operate the valve, and lean burn operation of the air-fuel ratio of the air-fuel mixture supplied to the engine when the magnitude of the temporal change rate of the control amount detection value is within a set range. Steady-state fuel injection amount control means for controlling the amount of fuel injection from the fuel injection device to a value suitable for When the rate of change exceeds the set range, the air-fuel ratio of the air-fuel mixture supplied to the engine during the lean burn operation is increased in order to increase the engine output at the same throttle opening with respect to the lean burn operation. A load suddenly increasing fuel injection amount control means for controlling the amount of fuel injection from the fuel injection device so as to change stepwise to a rich set air-fuel ratio set to a richer side than the air-fuel ratio is provided.
[0017]
Here, the lean burn operation refers to operating the engine by performing lean combustion in the cylinder by setting the air-fuel ratio of the air-fuel mixture supplied to the cylinder of the engine to be leaner than the stoichiometric air-fuel ratio.
[0018]
The rich set air-fuel ratio is preferably set to a value between the output air-fuel ratio and the stoichiometric air-fuel ratio.
[0019]
Note that the output air-fuel ratio is an air-fuel ratio (= about 12) that gives the maximum value of the engine output torque when the air-fuel ratio is changed with the throttle valve opening and the engine speed kept constant.
[0020]
As described above, when the engine is operated in a state where the air-fuel mixture is lean while the air-fuel ratio of the air-fuel mixture is a value suitable for lean-burn operation during a steady operation in which the load fluctuation range is within the set range, reduction of the throttle loss and The fuel efficiency can be improved by improving the combustion efficiency.
[0021]
Generally, when the lean burn operation is performed, the air-fuel ratio is set to a value close to the stoichiometric air-fuel ratio, or the air-fuel ratio is set to a richer side than during the stoichiometric operation in order to increase the engine power ( The throttle valve is more open than when performing the rich operation (enriching the mixture).
[0022]
In the control device of the present invention, when the control amount tries to suddenly change due to a sudden increase in the load while the lean burn operation is being performed, for example, when the output voltage of the generator tries to decrease due to the sudden increase in the load The air-fuel ratio is changed stepwise from the air-fuel ratio during lean burn operation to the rich set air-fuel ratio by increasing the fuel injection amount.
[0023]
As described above, when the control amount shows a sudden change due to a sudden increase in the load (for example, when the output voltage of the generator shows a steep drop), the air-fuel ratio of the air-fuel mixture is increased from the air-fuel ratio during the lean burn operation. When the air-fuel ratio is changed stepwise to the set air-fuel ratio, the output of the engine is immediately increased without waiting for the control of the throttle valve to compensate for the change in the control amount. Can be prevented. Further, after the control for changing the air-fuel ratio of the air-fuel mixture in steps to the rich set air-fuel ratio is performed, the control for increasing the opening of the throttle valve by the amount calculated by the operation amount calculating means is performed. The output further increases, the change in the control amount is suppressed, and the target value is quickly settled.
[0024]
In the above example, the change in the control amount caused when the load suddenly increases is suppressed. However, an engine supplied with fuel by the fuel injection device and ignited by the ignition device, and an AC generator driven by the engine An engine for controlling an engine output so as to maintain a control value at a target value with respect to a change in load by using a parameter indicating a change when the load of the alternator changes as a control amount of the engine-driven power generation device having: In the control device of the drive generator, when suppressing a change in the control amount when the load is suddenly reduced, an actuator that operates the throttle valve of the engine and an amount in which the value of the control amount is reflected as the control amount detection value. A deviation calculating means for detecting and calculating a deviation between the control amount detection value and a control target value set for the control amount detection value; Operating amount calculating means for calculating an operating amount of the throttle valve necessary to reduce the deviation to zero, actuator driving means for driving the actuator so as to operate the throttle valve by the calculated operating amount, and a load. Load-decreasing engine that controls at least one of the fuel injection device and the ignition device so as to rapidly decelerate the engine when the magnitude of the temporal change rate of the control amount detection value when the control value decreases exceeds a set range. It is configured to include a deceleration means.
[0025]
The load deceleration engine deceleration means is configured to stop the fuel injection to the engine when the magnitude of the temporal change rate of the control amount detection value when the load is reduced exceeds a set range. It can be constituted by a load sudden decrease fuel injection control means for controlling the device.
[0026]
The load deceleration-time engine deceleration means may also stop the ignition operation of the engine when the magnitude of the temporal change rate of the control amount detection value when the load decreases exceeds a set range, or It may also be constituted by a sudden load reduction ignition control means for controlling the ignition device so as to retard the ignition timing.
[0027]
The above-mentioned sudden load decrease engine deceleration means may also stop the ignition operation of the engine when the magnitude of the temporal change rate of the control amount detection value when the load decreases exceeds a set range, or A load sudden ignition control means for controlling the ignition device to retard the timing; and an engine when the magnitude of the temporal change rate of the control amount detection value when the load is reduced exceeds a set range. And the fuel injection control means for controlling the fuel injection device so as to stop the supply of the fuel.
[0028]
The load-decreasing engine deceleration means also performs ignition so as to periodically thin out the ignition spark of the engine when the magnitude of the temporal change rate of the control amount detection value when the load decreases exceeds a set range. It may also be constituted by a sudden-load-decrease ignition control means for controlling the apparatus.
[0029]
The control amount is, for example, an output voltage of a generator. When the output frequency of the generator is controlled to be constant, the rotation speed of the generator is used as the control amount.
[0030]
When the power generation device targeted by the present invention has a configuration of a so-called inverter power generation device, in addition to the generator, a DC converter for converting an output voltage of the generator into a DC voltage, and an output of the DC converter. An inverter for converting the voltage to an AC voltage having a constant frequency is further provided. When the present invention is applied to such an engine-driven power generator, for example, the output voltage of the DC converter is used as a control amount, and the output voltage of the DC converter required to maintain the output voltage of the inverter at a set value. Can be controlled to keep the output of the generator at the target value.
[0031]
The temporal change rate of the control amount detection value can be detected by a time differential value of the deviation calculated by the manipulated variable calculation means (difference between the previously calculated deviation and the currently calculated deviation).
[0032]
As described above, when the control amount shows a steep change due to a sudden decrease in the load (for example, when the output voltage of the generator is about to increase), the ignition operation is stopped or the fuel injection operation is stopped. If the engine is suddenly decelerated by cutting the fuel or the like, when the control amount shows a steep change due to a sudden decrease in the load, the control of the throttle valve to compensate for the change in the control amount is started. The engine can be rapidly decelerated without waiting for a change in the control amount. When the change rate of the control amount returns to the set range, the ignition operation and the fuel injection operation return, but at this time, control for decreasing the opening of the throttle valve by the amount calculated by the operation amount calculation means has already been performed. Since the output of the engine is suppressed, the output voltage of the generator quickly settles to the target value.
[0033]
When it is particularly problematic to suppress a change in the control amount at the time of a sudden increase in the load, the fuel injection amount control means at the time of a sudden increase in the load may be provided as described above to suppress the change in the control amount due to the sudden increase in the load. Well, if it is particularly problematic to suppress a change in the control amount at the time of a sudden decrease in the load, a sudden load decrease engine deceleration means may be provided to suppress the change in the control amount at the time of a sudden decrease in the load. However, when it is necessary to suppress both the change in the control amount at the time of the sudden increase in the load and the change of the control amount at the time of the sudden decrease in the load, the fuel injection amount control means during the sudden increase in the load and the load It is necessary to provide both of the sudden deceleration engine deceleration means.
[0034]
That is, when the load of the AC generator fluctuates in an engine-driven power generator including an engine supplied with fuel by a fuel injection device and ignited by an ignition device, and an AC generator driven by the engine. A control device for an engine-driven power generator that controls an engine output so as to keep the control amount at a target value with respect to the load variation, using a parameter indicating the change as a control amount. In the case of suppressing both changes in the control amount at the time of the rapid decrease, an actuator that operates the throttle valve of the engine and an amount that reflects the value of the control amount are detected as the control amount detection value, and the control amount detection value is detected. Deviation calculating means for calculating a deviation between the control target value and the control target value set for the control amount detection value, and a deviation calculating means for calculating the deviation calculated by the deviation calculating means to zero. Operating amount calculating means for calculating the operating amount of the throttle valve, actuator driving means for driving the actuator so as to operate the throttle valve by the calculated operating amount, and a time change rate of the control amount detected value. Steady-state fuel injection amount that controls the fuel injection amount from the fuel injection device so that the air-fuel ratio of the air-fuel mixture supplied to the engine when the size is within the set range is set to a value suitable for lean burn operation. Control means for increasing the engine output at the same throttle opening with respect to the lean burn operation when the magnitude of the temporal change rate of the control amount detection value when the load increases exceeds a set range; The air-fuel ratio of the air-fuel mixture supplied to the engine changes stepwise to the rich set air-fuel ratio that is set richer than the air-fuel ratio during lean burn operation. A sudden increase in the fuel injection amount control means for controlling the fuel injection amount from the fuel injection device, and the magnitude of the temporal change rate of the control amount detection value when the load decreases exceeds the set range. A load sudden-decrease engine deceleration means for controlling at least one of the fuel injection device and the ignition device so as to sometimes rapidly decelerate the engine is provided.
[0035]
As described above, the throttle valve for controlling the fuel injection device so as to immediately increase the fuel injection amount in a step-like manner when the control amount shows a sudden change due to a sudden increase in the load and compensating for the change in the control amount. If the control output shows a sudden change due to a sudden decrease in the load, the engine ignition operation is stopped or the ignition spark is thinned out and / or the fuel is cut off. Therefore, if the engine output is suppressed without waiting for the throttle valve control to start, the control amount will fluctuate greatly both when the load suddenly increases and when the load suddenly decreases. Thus, it is possible to obtain an engine-driven power generation device that can prevent the fluctuation and always perform a stable operation with respect to the load fluctuation.
[0036]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0037]
In the embodiment described below, a case where a configuration of an inverter generator in which an AC output of a generator is converted into a DC output by a DC converter and the DC output is converted into an AC voltage of a commercial frequency by an inverter is adopted. For example, the present invention is applied to a case where the output voltage of the generator detected from the output side of the DC converter is used as a control amount and the control amount is controlled to be maintained at a target value.
[0038]
FIG. 1 schematically shows the overall configuration of an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an engine whose intake air amount is adjusted by a throttle valve 2. The throttle valve 2 is operated by an electric actuator using a motor or the like as a drive source. The engine 1 may be a two-cycle engine or a four-cycle engine, but in the present embodiment, a four-cycle engine will be described as an example.
[0039]
A rotor of an AC generator 3 such as a magnet AC generator is attached to a crankshaft of the engine 1, and an output of the generator 3 is input to a DC converter 4 including a rectifier. The output of the DC converter 4 is input to the inverter 5, and the inverter 5 outputs an AC voltage having a constant frequency.
[0040]
The engine 1 is supplied with fuel by a fuel injection device FI including an injector (electromagnetic fuel injection valve) 11 and an injector driving unit 12 for driving the injector 11, and an ignition plug (not shown) attached to a cylinder head. ), And an ignition device IG including an ignition coil 13 for applying a high voltage to the ignition plug and an ignition coil drive unit 14 for driving the ignition coil 13.
[0041]
Although not shown, the injector 11 is supplied with fuel from a fuel tank through a fuel pump. The pressure of the fuel supplied to the injector 11 is kept almost constant by the pressure regulator.
[0042]
The injector drive unit 12 includes switch means such as a transistor which is turned on while an injection command signal is given, and turns on the switch means while the injection command signal is given. A drive current is supplied to the injector 11 from a power supply not to be used. The injector 11 opens its valve while a predetermined drive current is being supplied, and injects the fuel supplied by the fuel pump into an intake pipe of the engine or the like. Since the pressure of the fuel supplied from the fuel pump to the injector 11 is adjusted to a substantially constant value, the amount of fuel injected from the injector 11 is determined by the injection time.
[0043]
The ignition coil drive section 14 is a section that causes a sudden change in the primary current of the ignition coil 13 when an ignition signal is given to induce a high voltage for ignition in the secondary coil of the ignition coil. The coil driving unit can be configured by a capacitor discharge type circuit or a current cutoff type circuit.
[0044]
The ECU is an electronic control unit that controls the engine, and includes a control operation unit 15 including a microprocessor. In the illustrated example, an injector drive unit 12, an ignition coil drive unit 14, and a throttle drive unit 16 are provided in the control unit.
[0045]
As shown in FIG. 2, a microprocessor constituting the control operation unit 15 executes a predetermined program, and thereby, a control amount detection value corresponding to the output voltage (control amount) of the generator detected through the DC conversion unit 4. Deviation calculating means 21 for comparing Er with a control target value Et required to output a rated output voltage from the inverter 5 and calculating a deviation ΔE between the control amount detection value Er and the control target value Et; An operation amount calculating means 22 for performing a proportional / integral / differential operation on this deviation to calculate an operation amount of the throttle valve 2 required to make the deviation zero, and for operating the throttle valve by the calculated operation amount. And a throttle control unit that calculates a drive signal to be supplied to the actuator 6 and provides a command signal to the throttle drive unit 16 to instruct the throttle drive unit 16 to apply the calculated drive current to the actuator. Constitute a part 23.
[0046]
The throttle drive unit 16 is provided with a switch element such as a transistor for turning on / off a current supplied from a DC power supply (not shown) to the actuator 6 and a switch element such that a drive current calculated by the throttle control unit 23 flows through the actuator. Switch control means for turning on and off at a duty ratio of
[0047]
The control operation unit 15 includes an output Sp of a pulser that generates a pulse signal at a predetermined crank angle position of the engine 1, an output SA / F of an air-fuel ratio sensor that detects an air-fuel ratio supplied to a cylinder of the engine, and a throttle valve. In addition to the input of the throttle opening detection signal Thv output from the throttle sensor attached to the operation shaft 2 and the detection value Pa of the pressure (intake pressure) in the intake pipe of the engine, fuel injection such as engine temperature and atmospheric pressure is performed. Outputs of various sensors for detecting information necessary for calculating the amount are input.
[0048]
The control calculation unit 15 also executes a predetermined program to execute a rotation speed detection unit (not shown) for detecting the rotation speed of the engine from the pulser output Sp, a control amount change rate determination unit 30, The fuel injection control unit 24, the rapid load increase injection control unit 25, the rapid load decrease injection control unit 26, the ignition control unit 27, and the rapid load decrease ignition control unit 28 are configured.
[0049]
The control amount change rate determining means 30 detects a temporal change rate of the control amount detection value Er and determines whether or not the magnitude of the change rate is within a set range. Then, the differential value of the deviation ΔE calculated by the manipulated variable calculator 22 is detected as the temporal change rate of the control amount detection value Er, and the temporal change rate is compared with a determination value, whereby the control amount change It is determined whether or not the magnitude of the rate is within a set range.
[0050]
The constant fuel injection control means 24 controls the fuel injection amount in a steady state in which the magnitude of the temporal change rate of the control amount is within a set range. When the magnitude of the temporal change rate of the detection value is determined to be within the set range, the air-fuel ratio of the air-fuel mixture detected by the air-fuel ratio sensor is made to match a value suitable for lean burn operation. The fuel injection amount from the fuel injection device is controlled.
[0051]
The steady-state fuel injection control means 24 includes, for example, an intake air amount estimating means for estimating an intake air amount (by a throttle speed method) from an engine speed and a throttle valve opening, and A basic injection time calculating means for calculating a basic injection time necessary for setting an air-fuel ratio to a target air-fuel ratio during lean burn operation, and correcting the basic injection time for various control conditions such as atmospheric pressure and engine temperature. An actual injection time calculating means for performing feedback correction of the injection time based on the air-fuel ratio detected by the air-fuel ratio sensor and calculating an actual injection time by adding an invalid injection time; and injecting fuel for each rotational speed of the engine. Injection timing detection means for detecting the timing of starting the injection, and actual injection time calculation means for calculating when the injection timing is detected. The injection command signal having a signal width corresponding to the actual injection time are can be configured by the steady-state injection command means for applying to the injector drive unit 12.
[0052]
The load sudden increase injection control means 25 is a means for performing control for increasing the engine output before the control of the throttle valve for compensating for the change in the control amount is started when the load suddenly increases. When the magnitude of the temporal change rate of the control amount detected value exceeds the set range, the mixture supplied to the engine is increased to increase the engine output at the same throttle opening with respect to the lean burn operation. The fuel injection amount from the fuel injection device FI is controlled such that the air-fuel ratio of the air is changed stepwise to a rich set air-fuel ratio that is set richer than the air-fuel ratio during the lean burn operation. It is preferable that the rich set air-fuel ratio is set to an appropriate value in the range of not more than the stoichiometric air-fuel ratio (about 14.7) and not less than the output air-fuel ratio (= about 12). Here, the output air-fuel ratio is the air-fuel ratio that gives the maximum output of the engine for each throttle valve opening when the rotation speed is constant, and the engine uses the air-fuel ratio of the mixture as the output air-fuel ratio. Then, the maximum output torque is generated at each throttle valve opening.
[0053]
The sudden load increase injection control means 25 can be configured in the same manner as the steady-state injection amount control means, except that the target value of the air-fuel ratio is set to a preset rich set air-fuel ratio.
[0054]
Further, the load sudden decrease injection control means 26 stops the supply of fuel to the engine 1 when the magnitude of the temporal change rate of the control variable detection value when the load on the generator decreases exceeds a set range. The control means controls the fuel injection device such that, for example, the control amount change rate determining means 30 sets the magnitude of the temporal change rate of the control amount detection value when the load on the generator decreases. When it is detected that the range has been exceeded, the switching means of the injector driving unit 12 is prevented from being turned on, and the supply of the driving current to the injector 11 can be prohibited. .
[0055]
The ignition control unit 27 is a means for controlling the ignition timing in a state where the load of the generator does not suddenly decrease. This control means controls, for example, the control conditions such as the engine speed and the throttle valve opening degree. Ignition timing calculating means for calculating an optimal ignition timing of the engine, an ignition timing detecting means for detecting an ignition timing calculated for each rotation speed of the engine, and an ignition coil driving unit when the ignition timing is detected. And an ignition signal generating means for generating an ignition signal to be given to the control signal.
[0056]
In addition, the load sudden decrease point ignition control means 28 is means for decelerating the engine without waiting for the start of the control of the throttle valve for compensating the change in the control amount when the load suddenly decreases, In order to stop the ignition operation of the engine 1 or reduce the ignition timing to reduce the rotational speed when the magnitude of the temporal change rate of the control amount detection value Er when the load decreases exceeds a set range. The ignition device IG is controlled so as to be retarded by a necessary amount.
[0057]
For example, when the load control unit detects that the magnitude of the temporal change rate of the control amount detection value Er when the load is reduced exceeds a set range, the ignition control unit 27 controls the ignition control unit 27 when the load decreases. It can be constituted by means for inhibiting the application of the ignition signal to the ignition coil drive unit 14 or for delaying the timing (ignition timing) at which the ignition signal is applied.
[0058]
In the example shown in FIG. 2, the magnitude of the temporal change rate of the control amount detection value Er when the load is reduced is set by the sudden load decrease injection control means 26 and the rapid load decrease ignition control means 28. A sudden load decrease engine deceleration means for controlling the fuel injection device FI and the ignition device IG so as to rapidly decelerate the engine when the range is exceeded is provided.
[0059]
In the engine-driven power generator shown in FIGS. 1 and 2, when the engine 1 is started to operate the generator, the ECU reduces the air-fuel ratio A / F to warm up the air-fuel mixture in a rich state. Operate (when the engine is cold). When the warm-up of the engine is completed, the stoichiometric operation is usually performed with the air-fuel ratio set to the stoichiometric air-fuel ratio (approximately 14.7). While gradually changing the air-fuel ratio toward the target air-fuel ratio set on the lean side as much as possible, while controlling the throttle valve by feeding back the output voltage of the generator so as not to lower the output voltage of the generator, Shift from stoichiometric operation to lean burn operation while gradually opening the throttle valve.
[0060]
In the control device according to the present embodiment, after shifting the operation mode of the engine to the lean burn operation mode, the steady-state fuel injection control means 24, the sudden load increase injection control means 25, the sudden load decrease injection control means 26, and the sudden load decrease FIG. 3 shows an example of an algorithm of a task to be executed by a microprocessor constituting the control arithmetic unit 15 in order to realize the ignition control means 28.
[0061]
The task of FIG. 3 is to perform a stoichiometric operation once the warm-up operation of the engine is completed and then to shift to a lean burn operation and enter a steady operation state, and thereafter, at regular intervals (for example, every 2 msec). Executed).
[0062]
In the case of the algorithm shown in FIG. 3, first, in step 1, the output voltage of the DC converter 4 is detected as the control amount detection value Er, and then, in step 2, the deviation ΔE = Et−Er is calculated. Next, in step 3, a proportional / integral / differential operation (PID operation) is performed on the deviation ΔE to calculate an operation amount Cont of the throttle valve. When the proportional, integral, and derivative terms of the proportional, integral, and differential operations are CP, CI, and CD, respectively, the manipulated variable Cont is
Cont = CP + CI + CD (1)
When the deviation calculated this time is ΔEo, the deviation calculated last time is ΔE-1, ΔE-2,..., And kP, kI, and kD are the gains of the proportional term, the integral term, and the differential term, respectively,
CP = kP * ΔEo (* is a multiplication symbol) (2)
CI = kI * (ΔEo + ΔE-1 + ΔE-2 +...) (3)
CD = kD * (ΔEo−ΔE-1) (4)
After calculating the manipulated variable Cont in step 3, the differential term CD is compared with the determination value D1 in step 4, and if CD> D1, the process proceeds to step 5. In step 5, the differential term CD is compared with a determination value D2 (<D1). If CD <D2 is not satisfied (D1 <CD <D2), the process proceeds to step 6 where the control mode is changed to a mode for performing lean burn operation. After migration, move to other tasks.
[0063]
If it is determined in step 4 that CD> D1, the process proceeds to step 7, in which the engine is richly operated with the air-fuel ratio of the air-fuel mixture being smaller than the stoichiometric air-fuel ratio (the air-fuel mixture is in a rich state). Shift to rich operation mode.
[0064]
When it is determined in step 5 that CD <D2, the process proceeds to step 8 to stop fuel injection, stop the ignition operation, and shift to another task.
[0065]
In the case of the algorithm shown in FIG. 3, step 2 constitutes the deviation computing means 21 and step 3 constitutes the operation amount computing means 22. Steps 4 and 5 constitute the control amount change rate determining means 30, and step 6 constitutes the steady-state fuel injection control means 24. Step 7 constitutes a sudden load increase injection control means 25, and step 8 constitutes a sudden load decrease injection control means 26 and a sudden load decrease ignition control means 28.
[0066]
FIG. 4 shows the output torque τ vs. air / fuel ratio A / F characteristics when the rotation speed of the engine is constant and the throttle valve opening θ is changed as θ1, θ2, θ3, θ4 (θ1 <θ2 <θ3 <θ4). FIG. In the figure, point A indicates an operating point during stoichiometric operation at a certain rotational speed. When shifting from this state to the lean burn operation, the air-fuel ratio is changed to the target air-fuel ratio (about 14.7 in the illustrated example) during the lean burn operation while gradually changing the throttle valve opening from θ2 to θ3. The operating point is gradually increased toward the point B.
[0067]
As described above, when the engine is operated in a state where the air-fuel mixture is lean while the air-fuel ratio of the air-fuel mixture is a value suitable for lean-burn operation during a steady operation in which the load fluctuation range is within the set range, reduction of the throttle loss and The fuel efficiency can be improved by improving the combustion efficiency. When the lean burn operation is performed, the output of the engine slightly decreases, but the amount of HC and CO in the exhaust gas can be reduced. For reference, FIG. 5 shows an example of the relationship between the engine output torque τ, the amount of HC emission, the amount of CO emission, and the amount of NOx emission, and the air-fuel ratio A / F.
[0068]
Generally, when lean burn operation is performed, stoichiometric operation (operation in which the air-fuel ratio is set to a value near the stoichiometric air-fuel ratio) or rich operation (to increase the engine power, the air-fuel ratio is set to be richer than during stoichiometric operation). The throttle valve is more open than when performing the operation set on the side.
[0069]
In the control device of the present invention, as described above, in the state where the throttle valve is opened and the lean burn operation is performed as compared with the time of the stoichiometric operation or the rich operation, the control amount tends to change abruptly due to a sudden increase in the load. At this time (in the present embodiment, when the output voltage of the generator is about to suddenly decrease due to a sudden increase in load), the fuel injection amount is increased to change the air-fuel ratio from the stoichiometric air-fuel ratio (about 14.7) to the output air-fuel ratio ( The air-fuel ratio is reduced stepwise to the rich set air-fuel ratio set to about 12).
[0070]
As described above, when the control amount shows a sudden change due to a sudden increase in the load (for example, when the output voltage of the generator shows a steep drop), the air-fuel ratio of the air-fuel mixture is reduced in a stepwise manner. In, since the operating point immediately shifts from point B to point C (when the rich set air-fuel ratio is the stoichiometric air-fuel ratio) or point D (when the rich set air-fuel ratio is the output air-fuel ratio), the change in the control amount is compensated. The engine output torque τ is increased without waiting for the control of the throttle valve to be performed. As a result, a decrease in the rotation speed of the engine is suppressed, so that it is possible to prevent the output voltage of the generator from dropping significantly. After the control for decreasing the air-fuel ratio of the air-fuel mixture in a stepwise manner is performed, the control for increasing the opening of the throttle valve by the amount calculated by the manipulated variable calculating means 22 is performed, so that the output of the engine further increases. Thus, a change in the output voltage (control amount) of the generator is suppressed, and the output voltage is quickly settled to the target value.
[0071]
In the control device of the present embodiment, when the control amount shows a sudden change due to a sudden decrease in the load (in this example, when the output voltage of the generator is about to increase), the ignition operation is stopped. While cutting the ignition, the fuel injection operation is stopped to cut the fuel. In this way, when a sudden decrease in the load is detected, if the ignition of the engine is cut or the fuel is cut, the control of the throttle valve for compensating the change in the control amount is started. Without waiting, the engine can be rapidly decelerated to suppress a change in the control amount, so that a large change in the control amount due to a sudden decrease in the load can be prevented. When the magnitude of the temporal change rate of the control amount due to the load fluctuation returns to the set range, the ignition operation and the fuel injection operation are restored. At this time, the opening degree of the throttle valve is reduced by the amount calculated by the operation amount calculation means. , The output of the generator is quickly settled at the target value.
[0072]
FIG. 6 shows a case where only the opening degree of the throttle valve is controlled to compensate for a change in the output voltage of the DC power supply unit when the load power WL increases in a substantially step-like manner in the engine-driven power generator according to the present embodiment. And a response characteristic in the case where the control for changing the air-fuel ratio to the rich side and the control for the opening degree of the throttle valve are used together as in the present invention. When only the opening of the throttle valve is controlled to compensate for the change in the output voltage Er of the DC power supply unit (in the case of the conventional control), the load power WL at time t1, as shown by the solid line in FIG. Increases substantially stepwise, the output voltage Er of the DC converter shows a steep drop, and the voltage Er drops significantly. After the voltage Er decreases, the opening degree θ of the throttle valve gradually increases. The output We of the engine increases with a delay of a certain time from the change in the opening degree of the throttle valve, and accordingly, the output of the generator increases, and the output voltage Er of the DC converter is settled to the target value.
[0073]
On the other hand, according to the present invention, when the load power increases stepwise at time t1, the air-fuel ratio is first changed to the rich side, and the engine output We is output as shown by the broken line in FIG. Is immediately increased, so that the decrease in the voltage Er is suppressed as shown by the broken line.
[0074]
In the above embodiment, the ignition operation of the engine is stopped or the ignition timing is retarded when the magnitude of the temporal change rate of the control amount detection value when the load decreases exceeds a set range. And a fuel supply control means for controlling the ignition device when the load suddenly decreases, and stopping the supply of fuel to the engine when the magnitude of the temporal change rate of the control amount detection value when the load decreases exceeds a set range. A sudden load decrease fuel injection control means for controlling the fuel injection device so as to control the fuel injection device so as to constitute a sudden load decrease engine deceleration means to stop the ignition operation of the engine or delay the ignition timing when the load suddenly decreases. Although the angle is changed and the fuel is cut, the present invention is not limited to such a configuration, and the magnitude of the temporal change rate of the control amount detection value when the load decreases is reduced. When the load exceeds a predetermined range, the sudden load decrease engine deceleration means may be constituted only by the sudden load decrease fuel injection control means for controlling the fuel injection device so as to stop the supply of fuel to the engine. Good.
[0075]
Further, the ignition device is configured to stop the ignition operation of the engine or to retard the ignition timing when the magnitude of the temporal change rate of the control amount detection value when the load decreases exceeds the set range. The sudden load decrease engine deceleration means may be constituted only by the load sudden decrease fire control means to be controlled.
[0076]
Further, when the magnitude of the temporal change rate of the control amount detection value when the load decreases exceeds the set range, the ignition device controls the ignition device so as to periodically thin out the ignition spark of the engine. The control means may constitute a sudden load decrease engine deceleration means.
[0077]
In the above embodiment, the air-fuel ratio is feedback-controlled using the air-fuel ratio sensor. However, the present invention can also be applied to a case where the air-fuel ratio is controlled in an open loop without using the air-fuel ratio sensor. .
[0078]
In the above example, the intake air amount is estimated from the engine speed and the throttle valve opening. However, the intake air amount is estimated from the engine speed and the pressure in the intake pipe downstream of the throttle valve. The present invention can also be applied to the case of estimating (using the speed density method).
[0079]
In the above embodiment, an electric actuator using a motor or the like as a drive source is used as an actuator for operating the throttle valve. However, the present invention can be applied to a case where a hydraulic actuator is used.
[0080]
In the above embodiment, by performing proportional, integral, and derivative calculations on the deviation calculated by the deviation calculation means, the operation amount calculation means is configured to calculate the operation amount of the throttle valve required to make the deviation zero. However, when calculating the amount of operation of the throttle valve required to reduce the deviation to zero, it is not always necessary to perform both integral and differential operations on the deviation. By applying at least one of the above, the present invention can also be applied to the case where the operation amount of the throttle valve required to reduce the deviation to zero is calculated.
[0081]
【The invention's effect】
As described above, according to the present invention, when a parameter of a generator in which a change in load is reflected is set as a control amount, and the control amount is controlled so as to maintain a target value with respect to the change in load, a load When a sudden change in the control amount due to a sudden increase is detected, the fuel injection device is controlled so that the fuel injection amount is increased stepwise immediately, and control of the throttle valve for compensating for the change in the control amount is started. Since the output of the engine is increased before the load increases, there is an advantage that it is possible to prevent the control amount from greatly changing when the load suddenly increases.
[0082]
Further, according to the present invention, when a sudden change in the control amount due to a sudden decrease in the load is detected, the change in the control amount is reduced by causing the engine to cut off the ignition or to thin out the ignition spark and / or to cut off the fuel. Since the output of the engine is suppressed without waiting for the control of the throttle valve for compensation to be started, there is an advantage that it is possible to prevent a significant change in the control amount when the load suddenly decreases.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of an embodiment of the present invention.
FIG. 2 is a block diagram showing the configuration of the control unit of FIG. 1 in further detail.
3 is a flowchart illustrating an algorithm of a program executed by a microprocessor of a control operation unit of the control unit illustrated in FIG. 2;
FIG. 4 is a graph showing an example of output torque versus air-fuel ratio characteristics when the throttle valve opening is variously changed while the rotation speed of the engine is constant.
FIG. 5 is a graph showing an example of the relationship between the air-fuel ratio and the engine torque, HC emission, CO emission, and NOx emission.
FIG. 6 is a graph showing a comparison between response characteristics of a conventional control device and a control device according to the present invention when a load is rapidly increased.
FIG. 7 is a block diagram showing a configuration of a conventional control device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Throttle valve, 3 ... Generator, 4 ... DC conversion part, 5 ... Inverter, 6 ... Actuator, 13 ... Ignition coil, 14 ... Ignition coil drive part, 15 control operation part, 16 ... Throttle drive part .., 21: deviation calculating means, 22: manipulated variable calculating means, 23: throttle control unit, 24: steady-state fuel injection control means, 25: injection control means for sudden increase in load, 26: injection control means for sudden decrease in load, 27: ignition Control unit, 28: ignition control unit at the time of sudden decrease in load, 30: control amount change rate determination unit, IG: ignition device, FI: fuel injection device.

Claims (13)

When the load of the AC generator fluctuates when the load of the AC generator fluctuates, the fuel is supplied by the fuel injection device, and the engine is driven by the ignition device and includes an AC generator driven by the engine. A control device for an engine-driven power generator that controls an engine output so as to maintain the control amount at a target value with respect to the variation of the load, with the parameter shown as a control amount,
An actuator for operating a throttle valve of the engine;
Deviation calculating means for detecting an amount reflecting the value of the control amount as a control amount detection value, and calculating a deviation between the control amount detection value and a control target value set for the control amount detection value; ,
An operation amount calculating means for calculating an operation amount of the throttle valve required to make the deviation calculated by the deviation calculating means zero;
Actuator driving means for driving the actuator to operate the throttle valve by the calculated operation amount;
The fuel injection device is configured to set the air-fuel ratio of the air-fuel mixture supplied to the engine to a value suitable for lean burn operation when the magnitude of the temporal change rate of the control amount detection value is within a set range. Steady-state fuel injection amount control means for controlling the fuel injection amount from the
When the magnitude of the temporal change rate of the control amount detection value when the load increases exceeds the set range, the engine output at the same throttle opening with respect to the lean burn operation is increased. The amount of fuel injection from the fuel injection device is changed so that the air-fuel ratio of the air-fuel mixture supplied to the engine changes stepwise to a rich set air-fuel ratio set to a richer side than the air-fuel ratio during the lean burn operation. Control means for controlling the fuel injection amount at the time of sudden increase in load,
A control device for an engine-driven power generator, comprising: The control device for an engine-driven power generator according to claim 1, wherein the rich set air-fuel ratio is set to a value between an output air-fuel ratio and a stoichiometric air-fuel ratio. When the load of the AC generator fluctuates when the load of the AC generator fluctuates, the fuel is supplied by the fuel injection device, and the engine is driven by the ignition device and includes an AC generator driven by the engine. A control device for an engine-driven power generator that controls an engine output so as to maintain the control amount at a target value with respect to the variation of the load, with the parameter shown as a control amount,
An actuator for operating a throttle valve of the engine;
Deviation calculating means for detecting an amount reflecting the value of the control amount as a control amount detection value, and calculating a deviation between the control amount detection value and a control target value set for the control amount detection value; ,
An operation amount calculating means for calculating an operation amount of the throttle valve required to make the deviation calculated by the deviation calculating means zero;
Actuator driving means for driving the actuator to operate the throttle valve by the calculated operation amount;
When at least one of the fuel injection device and the ignition device is controlled so that the engine is rapidly decelerated when the magnitude of the temporal change rate of the control amount detection value when the load decreases exceeds a set range. Engine deceleration means when the load suddenly decreases,
A control device for an engine-driven power generator, comprising: When the load of the AC generator fluctuates when the load of the AC generator fluctuates, the fuel is supplied by the fuel injection device, and the engine is driven by the ignition device and includes an AC generator driven by the engine. A control device for an engine-driven power generator that controls an engine output so as to maintain the control amount at a target value with respect to the variation of the load, with the parameter shown as a control amount,
An actuator for operating a throttle valve of the engine;
Deviation calculating means for detecting an amount reflecting the value of the control amount as a control amount detection value, and calculating a deviation between the control amount detection value and a control target value set for the control amount detection value; ,
An operation amount calculating means for calculating an operation amount of the throttle valve required to make the deviation calculated by the deviation calculating means zero;
Actuator driving means for driving the actuator to operate the throttle valve by the calculated operation amount;
The fuel injection device is configured to set the air-fuel ratio of the air-fuel mixture supplied to the engine to a value suitable for lean burn operation when the magnitude of the temporal change rate of the control amount detection value is within a set range. Steady-state fuel injection amount control means for controlling the fuel injection amount from the
When the magnitude of the temporal change rate of the control amount detection value when the load increases exceeds the set range, the engine output at the same throttle opening with respect to the lean burn operation is increased. The amount of fuel injection from the fuel injection device is changed so that the air-fuel ratio of the air-fuel mixture supplied to the engine changes stepwise to a rich set air-fuel ratio set to a richer side than the air-fuel ratio during the lean burn operation. Control means for controlling the fuel injection amount at the time of sudden increase in load,
When at least one of the fuel injection device and the ignition device is controlled so that the engine is rapidly decelerated when the magnitude of the temporal change rate of the control amount detection value when the load decreases exceeds a set range. Engine deceleration means when the load suddenly decreases,
A control device for an engine-driven power generator, comprising: The control device for an engine-driven power generator according to claim 4, wherein the rich set air-fuel ratio is set to a value between an output air-fuel ratio and a stoichiometric air-fuel ratio. The load deceleration-time engine deceleration means is configured to stop supplying fuel to the engine when a magnitude of a temporal change rate of the control amount detection value when the load is reduced exceeds a set range. 5. The control device for an engine-driven power generator according to claim 3, further comprising a fuel injection control means for suddenly decreasing the load for controlling the fuel injection device. The load sudden decrease engine deceleration means may stop the ignition operation of the engine when the magnitude of the temporal change rate of the control amount detection value when the load decreases exceeds a set range, or The control device for an engine-driven power generator according to claim 3 or 4, further comprising a load sudden ignition control means for controlling the ignition device so as to retard the ignition timing of the engine. The load sudden decrease engine deceleration means may stop the ignition operation of the engine when the magnitude of the temporal change rate of the control amount detection value when the load decreases exceeds a set range, or A load sudden ignition control means for controlling the ignition device so as to retard the ignition timing of the engine, and the magnitude of the temporal change rate of the control amount detection value when the load decreases is within the set range. 5. The control of the engine-driven power generator according to claim 3, further comprising a fuel-injection-control-means for suddenly decreasing the load that controls the fuel injection device so as to stop the supply of fuel to the engine when the engine speed exceeds the limit. 6. apparatus. The load deceleration-time engine deceleration means is configured to periodically thin out the ignition spark of the engine when a magnitude of a temporal change rate of the control amount detection value when the load is reduced exceeds a set range. 5. The control device for an engine-driven power generator according to claim 3, further comprising: a load sudden ignition control means for controlling the ignition device. The control device for an engine-driven power generator according to any one of claims 1 to 9, wherein the control amount is an output voltage of the generator. The control device for an engine-driven power generator according to any one of claims 1 to 9, wherein the control amount is a rotation speed of the generator. A DC converter for converting the output voltage of the generator to a DC voltage; and an inverter for converting the output voltage of the DC converter to an AC voltage having a constant frequency,
The control amount is an output voltage of the DC converter,
The control device for an engine-driven power generator according to any one of claims 1 to 9, wherein the control target value is an output voltage value of the DC converter required to keep an output voltage of the inverter at a set value. The control device for an engine-driven power generator according to any one of claims 1 to 12, wherein the temporal change rate of the control amount detection value is detected by a time differential value of the deviation calculated by the operation amount calculation means. .

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