JP5871140B2 - Electronic governor for engine - Google Patents

Description

  The present invention relates to an electronic governor for an engine that performs control for converging the rotational speed of an engine to a target rotational speed.

  In an apparatus such as an automobile that operates using an engine as a drive source, an electronic governor that performs control for converging the actual rotational speed of the engine to a target speed by feedback control is used. As shown in FIG. 6, the engine electronic governor 1 includes a mixture supply amount adjustment unit 3 that adjusts the supply amount of fuel and air to the engine 2, and a signal that includes information on the actual rotational speed of the engine 2. Rotation speed detection means 5 for detecting the actual rotation speed of the engine from the output of the rotation sensor 4 that outputs a rotation speed detection signal Vn and a target speed setter 6 for setting the target rotation speed of the engine. Rotational speed deviation calculating means 7 for calculating a deviation Vno−Vn between the speed setting signal Vno and the rotational speed detection signal Vn, a control gain setting unit 8 ′ for setting a proportional gain P, an integral gain I and a differential gain D, and a control Using the proportional gain P, integral gain I, and differential gain D set by the gain setting unit 8 ', the deviation (Vno-Vn) is reduced to zero by performing proportional, integral, and differential operations on the deviation (Vno-Vn). The operation amount calculation means 9 for outputting the control signal Vq that gives the operation amount of the air-fuel mixture supply amount adjustment unit 3 necessary for the control, and the operation amount calculated by the operation amount calculation means 9 with the control signal Vq as an input An operation signal output unit 10 that outputs an operation signal to be supplied to the mixture supply amount adjustment unit 3 in order to operate the mixture supply amount adjustment unit 3 is provided.

The manipulated variable calculation means 9 uses the proportional gain P, integral gain I and differential gain D set by the control gain setting means, and is proportional to the deviation (Vno−Vn), integral and differential calculations according to the following equation (1). To output a control signal Vq that gives an operation amount of the air-fuel mixture supply amount adjusting unit 3 necessary to make the deviation (Vno−Vn) zero.
Vq = P (Vno−Vn) + I∫ (Vno−Vn) dt + D {d (Vno−Vn) / dt} (1)

  The air-fuel mixture supply amount adjusting unit 3 adjusts the air-fuel mixture supply amount so as to supply the engine with fuel and air in an amount corresponding to the operation signal supplied from the operation signal output unit 10, and sets the engine rotation speed to the target rotation speed. To match.

  In an electronic governor that performs control for converging the rotational speed of the engine to a target rotational speed by PID control, performance such as control responsiveness and stability is determined by the control gains P, I, and D. When the control gain is set to a fixed value, if the control gain is set large in order to improve responsiveness, the stability will deteriorate, and if the load fluctuates finely or the target rotational speed is changed slightly, Speed overshoot and undershoot increase, and it takes time until the rotational speed converges to the target rotational speed. Also, if the control gain is set small to improve the stability, the responsiveness will deteriorate, and the overshoot and undershoot of the rotation speed will increase when the load fluctuates greatly or when the target rotation speed is changed greatly. Thus, the time required until the engine speed is converged to the target speed becomes longer. In addition, when the load increases significantly, engine stall may occur due to failure to supply the air-fuel mixture required by the engine.

  Therefore, as shown in Patent Document 1, using a three-dimensional control gain calculation map that gives the relationship among the target rotation speed, the rotation speed deviation, and the control gain, the target rotation speed, the rotation speed deviation, On the other hand, it has been proposed to set the control gain for each value of the target rotational speed and the rotational speed deviation by searching this map.

  In the above description, the operation amount necessary for making the engine speed coincide with the target speed is calculated by calculating the first to third terms on the right side of the equation (1). In order to make the rotational speed coincide with the target rotational speed, only the operation amount calculation P (Vno−Vn) using the proportional gain P is essential, and the integral calculation of the rotational speed deviation using the integral gain I is required. A differential operation D {d (Vno−Vn) / dt} of rotational speed deviation using I∫ (Vno−Vn) dt and a differential constant is added as necessary. The second term on the right side of the equation (1) that performs the integral calculation of the deviation using the integral gain I is added when it is necessary to particularly reduce the residual deviation that occurs between the rotational speed and the target rotational speed. Further, the third term on the right side of the equation (1) for performing the differential operation of the differential using the differential gain D is added when preventing hunting from occurring due to a rapid change in the rotational speed.

JP 2009-36180 A

  As in the invention disclosed in Patent Document 1, the control gain is determined for each value of the target rotational speed and the rotational speed deviation by searching the map for the target rotational speed and the rotational speed deviation. As a result, the control gain can be set finely with respect to the target rotational speed and the rotational speed deviation, so that the engine rotational speed can be controlled more accurately than when the control gain is fixed. Can do. However, as described below, the optimum control can be performed by the invention described in Patent Document 1 only when the target rotational speed is kept constant and a rotational speed deviation occurs due to load fluctuation. The control gain cannot be set to an optimum value when a rotational speed deviation is caused by appropriately changing the target rotational speed.

  In general, in an electronic governor that performs control for converging the engine rotational speed to a target rotational speed by PID control, an optimal control gain and load when a rotational speed deviation occurs due to load fluctuation while the target rotational speed is constant. When a rotational speed deviation occurs due to a change in the target rotational speed in a state where there is no fluctuation, the optimal control gain does not match. Therefore, when the target rotational speed may be appropriately changed during engine operation, the target rotational speed may vary due to load fluctuations while the target rotational speed is constant, and the target rotational speed may be varied without load fluctuations. Unless the rotational speed deviation is caused by the change in speed and the control gain is set to a value suitable for each case, optimal control cannot be performed.

  However, according to the invention disclosed in Patent Document 1, when the target rotational speed is constant and the rotational speed deviation is caused by the load fluctuation, the target rotational speed is changed without the load fluctuation. Therefore, the control gain cannot be set accurately.

  For example, if the target rotational speed is changed when there is no engine load fluctuation and the actual rotational speed matches the target rotational speed (when the rotational speed deviation is zero), the change in the target rotational speed A rotational speed deviation equal to is generated, so even though the load is constant, the same state as the rotational speed deviation has occurred due to the fluctuation of the load, the cause of the rotational speed deviation is It cannot be specified whether the load is changing or the target rotational speed is changing. Therefore, according to the invention described in Patent Document 1, the case where the rotational speed deviation is caused by the load fluctuation and the case where the rotational speed deviation is caused by the change of the target rotational speed are distinguished and optimum in each case. The control gain cannot be set to the value of.

  In this case, creating a map that calculates the control gain so that optimal control can be performed when a rotational speed deviation occurs due to load fluctuations, it is optimal when the same rotational speed deviation occurs due to changes in the target rotational speed. If you create a map that calculates the control gain so that optimal control can be performed when a rotational speed deviation occurs due to a change in the target rotational speed, the same rotational speed deviation can be When this occurs, optimal control cannot be performed. Therefore, in the conventional electronic governor, the value of the control gain calculated by the map is a compromise between the case where the rotational speed deviation occurs due to the load fluctuation and the case where the rotational speed deviation occurs due to the change in the target rotational speed. Therefore, it is necessary to create a control gain calculation map so as to have a compromised value, and optimal control of the rotational speed cannot be performed.

  FIG. 7 shows the engine rotation when the load is changed by setting a control gain so that optimum control can be performed when a rotational speed deviation occurs due to a load fluctuation while the target rotational speed is constant. It shows the speed response. On the other hand, FIG. 8 shows the response of the rotational speed when the control gain is set to be the same as that in FIG. 7 and the target rotational speed is changed. As is apparent from FIG. 8, when the target rotation speed is changed in a state where the control gain is set so that optimum control is performed when the rotation speed fluctuates due to load fluctuation while the target rotation speed is constant. Is not preferable because the amount of operation becomes excessive and the rotational speed greatly exceeds the target rotational speed and then converges to the target rotational speed, resulting in large fluctuations in the rotational speed when switching the target rotational speed. .

  It is an object of the present invention to set the control gain to an optimum value in any case where a rotational speed deviation occurs due to a load change and a rotational speed deviation occurs due to a change in the target rotational speed, so that stability and response are set. It is an object to provide an electronic governor for an engine that makes it possible to perform optimal control that is both highly reliable.

  The present invention relates to an air-fuel mixture supply amount adjusting unit that adjusts fuel and air supply amounts (air-fuel mixture supply amount) to an engine, a control gain setting unit that sets a control gain, and a rotation that detects the rotational speed of the engine. Using speed detection means, rotation speed deviation calculation means for calculating a deviation between the target rotation speed of the engine and the rotation speed detected by the rotation speed detection means as a rotation speed deviation, and a control gain set by the control gain setting unit And an operation amount calculation means for calculating an operation amount of an air-fuel mixture supply amount adjustment unit necessary for converging the engine rotation speed to the target rotation speed by calculating the rotation speed deviation. Targeting an electronic governor for an engine that controls the engine speed to the target speed by operating the air-fuel mixture supply amount adjustment unit by the operation amount calculated by To. In the present specification, at least the first to fifth inventions are disclosed in order to achieve the above object in the engine electronic governor having the above-described configuration.

  In the first invention disclosed in the present specification, the control gain setting unit is generated when the target speed fluctuation control gain correction coefficient determined according to the fluctuation amount of the target rotational speed and the engine load fluctuate. The control gain used to calculate the manipulated variable is determined by correcting the reference value of the set control gain using both the control gain correction coefficient during load fluctuation determined according to the rotational speed deviation. Is done.

  As described above, the control gain correction coefficient at the time of target speed fluctuation determined according to the fluctuation amount of the target rotational speed, and the control gain correction coefficient at the time of load fluctuation determined according to the rotational speed deviation caused when the engine load fluctuates When the control gain is determined by correcting the reference value of the control gain using both of the above and the case, when the rotational speed deviation occurs due to the load fluctuation and when the rotational speed deviation occurs due to the change in the target rotational speed In any case, the control gain is set to an optimum value, and optimum control with high stability and responsiveness can be performed.

  The second invention disclosed in this specification is applied to the first invention. In the present invention, the sign of the rotational speed deviation and the change tendency of the rotational speed detected by the rotational speed detecting means Load variation determining means for determining whether or not the engine load varies and whether or not the control gain at the time of load variation needs to be corrected is provided. In this case, the control gain setting unit corrects the control gain when the load fluctuates according to the rotational speed deviation when it is determined by the load fluctuation determining means that the engine load fluctuates and the control gain needs to be corrected. Determine the coefficient.

  In the third invention disclosed in this specification, the control gain setting unit changes the target rotational speed by the target speed change determining means for determining whether or not the target rotational speed has changed, and the target speed change determining means. A target speed fluctuation amount calculating means for calculating a fluctuation amount of the target rotational speed when it is determined that the target rotational speed is determined, and a control used for calculating the operation amount when the target speed change determining means determines that the target rotational speed has changed. In order to obtain the gain, a target speed fluctuation gain correction coefficient to be multiplied by the reference value of the control gain is calculated with respect to the target rotational speed fluctuation amount calculated by the target speed fluctuation amount calculating means, and the target speed change determining means calculates the target When it is determined that the rotation speed has not changed, the target speed fluctuation control gain correction coefficient calculating means for setting the target speed fluctuation gain correction coefficient to 1, the rotation speed and the target rotation speed Load variation to determine whether the engine load has fluctuated and whether or not the control gain should be corrected when the load fluctuates, based on the magnitude relationship between the rotation speed and the rotational speed detected by the rotational speed detection means When the determination means and the load fluctuation determination means determine that the engine load fluctuates and it is necessary to correct the control gain when the load fluctuates, the control gain is used to obtain the control gain used for the operation amount calculation. Even if the load fluctuation control means determines that the engine load has not fluctuated, or the load fluctuates, When it is determined that correction of the control gain is unnecessary, the control gain correction coefficient calculation unit for the load fluctuation when the control gain correction coefficient for the load fluctuation is 1, and the reference value of the control gain. Control gain correction means comprising control gain correction means for correcting the control gain reference value by multiplying the speed fluctuation gain correction coefficient and the load fluctuation control gain correction coefficient to obtain the control gain used for calculating the manipulated variable The control gain corrected by the means is configured to be a control gain used for calculation of the operation amount.

  The fourth invention disclosed in this specification is applied to the third invention. In the present invention, the target rotation speed detected this time is set by detecting the target rotation speed every minute time. Target speed storage means for storing the target rotational speed attenuated by the ratio as the previous target rotational speed is provided. In this case, the target speed change determining means determines whether or not the target rotational speed has changed by comparing the target rotational speed detected this time with the previous target rotational speed stored in the target speed storage means. The target speed fluctuation amount calculating means is configured to calculate the amount of fluctuation of the target rotational speed by calculating the difference between the target rotational speed detected this time and the previous target rotational speed stored in the target speed storage means.

  The fifth invention disclosed in this specification is applied to the third invention or the fourth invention. In the present invention, the load fluctuation determining means is configured such that the engine speed is higher than the target speed. When a change in the increasing direction is detected in the engine rotational speed detected by the rotational speed detection means in a state that is determined to be high, the engine load is reduced and it is necessary to correct the control gain when the load fluctuates. When it is determined that the engine rotational speed is not higher than the target rotational speed and a change in the decreasing direction is detected in the engine rotational speed detected by the rotational speed detecting means, the engine load is It is determined that the control gain at the time of load fluctuation needs to be corrected, the engine rotational speed is determined to be higher than the target rotational speed, and the engine speed detected by the rotational speed detecting means is detected. When the change in the increasing direction is not detected in the engine rotation speed and when the engine rotation speed is determined not to be higher than the target rotation speed, and the change in the decrease direction is detected in the engine rotation speed detected by the rotation speed detecting means. Even if there is no change in the engine load when it is not detected, or even if the load fluctuates, it is determined that it is not necessary to correct the control gain when the load changes.

  The fifth invention disclosed in this specification is applied to the third invention, the fourth invention, or the fifth invention. In the present invention, the load fluctuation determining means is a rotation speed detecting means. It is configured to determine whether the rotational speed of the engine is in an increasing direction or a decreasing direction from a change in the moving average value of the detected rotational speed.

  According to the present invention, the control gain correction coefficient at the time of load fluctuation determined according to the control gain correction coefficient at the time of target speed fluctuation determined according to the fluctuation amount of the target rotation speed and the rotation speed deviation caused when the engine load fluctuates. Since the control gain is determined by correcting the reference value of the control gain using both the coefficient and the rotation speed deviation due to the load fluctuation, and when the rotation speed deviation occurs due to the change in the target rotation speed Even in this case, the control gain is set to an optimum value, and optimum control with high stability and responsiveness can be performed.

It is the block diagram which showed the structure of the engine system provided with the electronic governor which concerns on this invention. It is the block diagram which showed the structure of one Embodiment of the electronic governor which concerns on this invention. FIG. 3 is a diagram showing a part of a flowchart showing an algorithm of a governor control task that is executed by a microprocessor at a minute time interval in order to constitute each unit shown in FIG. 2 in the embodiment of the present invention. FIG. 5 is a diagram showing another part of a flowchart showing an algorithm of a governor control task that is executed by a microprocessor at a minute time interval in order to constitute each part shown in FIG. 2 in the embodiment of the present invention. A graph showing an example of a change in the target rotational speed Nt0 when the attenuation amount of the target rotational speed Nt0 to be detected at the time of the previous task execution is uniformly changed by the specified number of times when each governor control task is executed. is there. It is the block diagram which showed the structure of the engine system provided with the conventional electronic governor. It is the graph which showed an example of the response characteristic of the rotation speed of an engine at the time of changing load with the target rotation speed fixed. It is the graph which showed an example of the response characteristic of the rotational speed of an engine at the time of setting a control gain to the same setting as FIG. 7, and changing target rotational speed.

Hereinafter, an embodiment of an electronic governor for an engine according to the present invention will be described with reference to the drawings.
FIG. 1 shows the configuration of an engine system equipped with an electronic governor according to the present invention. In FIG. 1, 1 is an electronic governor that controls the rotational speed of the engine 2 to converge to a target speed, and 6 is an engine governor. It is a target speed setter composed of a changeover switch and the like operated when switching the target rotation speed. The target rotational speed set by the target speed setter 6 is given to the electronic governor 1. In addition to being switched by the target speed setting device 6, the target engine speed is also changed when an idle down request for reducing the engine speed to the idle speed is issued or when the idle down request is canceled. It is done.

  IG is an ignition device for igniting the engine 2, Tv is a throttle valve that is attached to the intake pipe of the engine and adjusts the supply amount of the air-fuel mixture supplied to the engine cylinder, and Bt is a battery that provides a power supply voltage to the electronic governor 1 It is. The battery Bt is charged through a charging device by a rectified output of a magnet type AC generator (not shown) driven by the engine 2.

  The ignition device IG includes an ignition coil having a primary coil and a secondary coil, the secondary coil being connected to an ignition plug of the engine, and an ignition circuit for controlling a primary current flowing through the primary coil of the ignition coil. The ignition circuit causes an abrupt change in the primary current of the ignition coil at the ignition timing of the engine, thereby inducing a high voltage for ignition in the secondary coil of the ignition coil to cause a spark in the spark plug. A high primary voltage is induced in the primary coil of the ignition coil every time the engine is ignited. The frequency of the primary voltage is proportional to the engine speed, and the generation interval is inversely proportional to the engine speed. In this embodiment, the primary coil of the ignition coil of the ignition device IG is used as a rotation sensor, and the rotational speed of the engine is detected from the generation interval of the primary voltage of the ignition coil.

  The electronic governor 1 includes a microprocessor having a CPU, a ROM, a RAM, and the like. The microprocessor repeatedly executes a governor control task program stored in the ROM every minute time, thereby setting the target engine speed. Various means necessary for realizing control for convergence to the rotational speed are configured.

  Referring to FIG. 2, the configuration of the electronic governor 1 of this embodiment is shown in a block diagram. The electronic governor 1 of the present embodiment includes an air-fuel mixture supply amount adjusting unit 3 that adjusts the amount of fuel and air supplied to the engine, a rotation speed detection unit 5, a target speed storage unit 21, and a rotation speed storage unit 22. The rotation speed deviation calculating means 7, the control gain setting means 8, the operation amount calculating means 9, and the operation signal output unit 10 are configured.

  The rotational speed detection means 5 is a means for detecting the actual rotational speed N (rpm) of the engine every minute time. In order to constitute the rotational speed detection means 5, in this embodiment, a primary voltage induced in the primary coil of the ignition coil of the ignition device IG is detected as an ignition primary signal when the engine is ignited, and this ignition primary signal is detected. Each time, the microprocessor that controls the rotational speed of the engine is caused to execute interrupt processing. In this interrupt processing, the time from when the previous ignition primary signal is generated until the current ignition primary signal is generated is measured as the ignition primary signal generation interval, and the engine rotation speed is calculated from this ignition primary signal generation interval. To do.

  The target speed storage means 21 detects the target rotational speed Nt of the engine set by the target speed setter 6 every minute (every time the microprocessor executes the governor control task), and the target rotational speed detected this time. Is a means for storing the target rotational speed obtained by attenuating at a set ratio as the previous target rotational speed.

  The rotational speed storage means 22 is means for sequentially storing the actual rotational speed of the engine at each detection timing, and detects the actual rotational speed N of the engine detected by the rotational speed detection means 5 at a detection timing that appears every minute time. The rotational speed N for the set number of detections is sequentially stored.

  The rotational speed deviation calculating means 7 calculates the rotational speed deviation dN by performing an operation of subtracting the actual rotational speed from the target rotational speed every minute time.

  The control gain setting unit 8 is a part for setting a control gain used for calculation of the operation amount. The target speed change determination means 8A, the target speed fluctuation amount calculation means 8B, the target speed fluctuation control gain correction coefficient calculation means 8C, The rotation speed average value calculation means 8D, load fluctuation determination means 8E, load fluctuation control gain correction coefficient calculation means 8F, and control gain correction means 8G. In the present embodiment, in order to simplify the description, among the three control gains of the proportional gain P, the integral gain I, and the differential gain D, only the proportional gain P is used to calculate the proportional calculation P (N -Nt), the manipulated variable is obtained, and the integral gain and the differential gain are not used for the calculation of the manipulated variable. That is, the manipulated variable is calculated only by the first term on the right side of equation (1).

  The target speed change determining means 8A is a means for determining whether or not the target rotational speed has changed (whether or not the target speed setter 6 has changed the target rotational speed). This means is used by the microcomputer as a governor control task. Whether or not the target rotational speed has changed by comparing the target rotational speed Nt detected this time with the target rotational speed Nt0 stored in the target speed storage means 21 as the previously detected target rotational speed each time Determine whether.

  When it is determined that the target rotational speed has changed, the target rotational speed fluctuation amount calculation means 8B calculates the difference Nt−Nt0 between the currently detected target rotational speed Nt and the previously detected target rotational speed Nt0 as the target rotational speed. It is a means for calculating as the fluctuation amount dNt.

  The control gain correction coefficient calculation means 8C at the time of target speed fluctuation is used to obtain the control gain used for calculating the manipulated variable when the target speed change determination means 8A determines that the target rotational speed Nt has changed. This is means for calculating the target speed fluctuation gain correction coefficient Cpt multiplied by the reference value Kp with respect to the target rotational speed fluctuation amount dNt calculated by the target rotational speed fluctuation amount calculation means 8B.

  The target speed fluctuation control gain correction coefficient calculation means 8C used in the present embodiment uses the target speed fluctuation gain correction coefficient calculation table as the target rotation speed when the target speed change determination means determines that the target rotation speed has changed. By searching for the fluctuation amount dNt, a target speed fluctuation gain correction coefficient Cpt is calculated. When the target speed change judging means determines that the target rotational speed has not changed, the target speed fluctuation gain correction coefficient Cpt is calculated. Is 1. The target speed fluctuation gain correction coefficient calculation table is a table (map) that gives the relationship between the target rotational speed fluctuation amount dNt and the target speed fluctuation gain correction coefficient Cpt. This table includes, for example, each target rotational speed fluctuation. It is created based on optimum data obtained from an experiment for examining the response characteristics of the rotational speed by varying the value of the gain correction coefficient Cpt at the time of target speed fluctuation with respect to the quantity dNt and stored in the ROM.

  The rotation speed average value calculation means 8D is a means for calculating the average value of the engine rotation speed detected by the rotation speed detection means 5. The rotational speed average value calculating means of the present embodiment is configured to calculate a moving average value Nv of the rotational speed of the engine detected by the rotational speed detecting means 5. The calculation of the moving average value Nv of the rotational speed is carried out for the detected value of the rotational speed detected at the current detection timing and the continuous n−1 times (n is an integer of 2 or more) appearing immediately before the current detection timing. This is performed by calculating an average value of the detected values of the total n rotational speeds, which are detected from the detection timing and stored in the rotational speed storage means 22 and n−1 rotational speed detected values.

  The load fluctuation determination means 8E is a means for determining whether or not the engine load has changed and whether or not correction of the control gain at the time of load fluctuation is necessary. The load fluctuation determination means 8E used in the present embodiment detects the rotation speed in a state where the engine rotation speed is determined to be higher than the target rotation speed from the sign of the rotation speed deviation dN calculated by the rotation speed deviation calculation means 7. When a change in the increasing direction is detected in the engine rotation speed detected by the means 5, it is determined that the engine load is decreasing and the control gain correction at the time of load fluctuation is necessary, and the sign of the rotation speed deviation is determined. When the engine rotational speed is determined to be lower than the target rotational speed, the engine load increases when a change in the decreasing direction is detected in the engine rotational speed detected by the rotational speed detecting means 5. It is determined that it is necessary to correct the control gain when the load fluctuates. Further, when it is determined from the sign of the rotational speed deviation dN that the engine rotational speed N is higher than the target rotational speed Nt, and no change in the increasing direction is detected in the engine rotational speed N detected by the rotational speed detecting means 5, When the engine rotational speed N is determined to be lower than the target rotational speed Nt from the sign of the rotational speed deviation dN and no change in the decreasing direction is detected in the engine rotational speed N detected by the rotational speed detecting means 5 Even if there is no fluctuation in the engine load, or even if the load fluctuates, it is determined that correction of the control gain at the time of load fluctuation is unnecessary because the engine rotation speed can converge to the target rotation speed.

  Here, if the rotational speed deviation dN is obtained by the formula dN = N−Nt, the rotational speed deviation dN becomes positive (the engine rotational speed N is higher than the target rotational speed Nt). When the target rotational speed Nt is changed in the decreasing direction, (b) when the engine load decreases and the rotational speed overshoots, and (c) the load increases and the rotational speed undershoot occurs. This is one of cases where the rotational speed N is increased because the operation amount of the air-fuel mixture supply amount adjusting unit in the subsequent control is excessive.

  The rotational speed deviation dN becomes negative (the engine rotational speed N becomes lower than the target rotational speed Nt). (D) When the target rotational speed is changed in the increasing direction, (e) the load increases. When an undershoot occurs in the rotation speed, and (f) the operation amount of the mixture supply amount adjustment unit in the control after the load decreases and the overspeed occurs in the rotation speed, the rotation speed N This is one of the cases where the drop is caused.

  Therefore, in a state where the rotational speed deviation dN (= N−Nt) is positive (a state where the engine rotational speed is higher than the target rotational speed), the engine rotational speed is increased from the moving average value Nv of the rotational speed. When it is determined that the load is decreasing, the rotational speed deviation dN (= N−Nt) is negative (the engine rotational speed is lower than the target rotational speed). When it is determined from the moving average value Nv of the rotation speed that the engine rotation speed is decreasing, it can be determined that the load is increasing.

  As described above, in this embodiment, a change in the increasing direction is detected in the engine rotation speed detected by the rotation speed detection means 5 in a state where the engine rotation speed is determined to be higher than the target rotation speed. Sometimes it is determined that the engine load is decreasing and it is necessary to correct the control gain when the load fluctuates, and the engine speed is detected by the rotation speed detection means 5 when it is determined that the engine rotation speed is lower than the target rotation speed. When a change in the decreasing direction is detected in the engine rotational speed, it is determined that the engine load is increasing and the control gain correction when the load fluctuates is necessary, but the rotational speed deviation dN (= N− In a state where Nt) is positive (a state where the engine rotational speed is higher than the target rotational speed), it is determined that a change in the increasing direction has occurred in the engine rotational speed from the moving average value Nv of the rotational speed. If the rotation speed deviation dN (= N−Nt) is negative (the engine rotation speed is lower than the target rotation speed), the moving average value Nv of the rotation speed is changed to the engine rotation speed. When it is not determined that a change in the decreasing direction has occurred, the control gain is corrected using the control gain correction coefficient during load fluctuation even if there is no fluctuation in the engine load or the load fluctuates. It is determined that there is no need. The reason for making such a determination is as follows.

That is, the state in which the engine rotational speed N is determined to be higher than the target rotational speed Nt and no change in the engine rotational speed is detected is any of the following states (A) to (C): is there.
(A) A state in which the rotational speed N becomes higher than the target rotational speed Nt because the load has once decreased, but the rotational speed subsequently decreases toward the target speed because the load has started to increase.
(B) Although the rotational speed N has become higher than the target rotational speed Nt because the load has once decreased, the control by the governor works effectively because there is no change in the load thereafter, and the rotational speed decreases toward the target speed. State to go.
(C) Although the load continues to decrease after the rotational speed N becomes higher than the target rotational speed Nt because the load has once decreased, control by the governor is not performed because the change in the load decreasing direction is not rapid. A state in which the rotation speed N works effectively and decreases toward the target rotation speed Nt.

A state in which it is determined that the engine rotational speed N is lower than the target rotational speed Nt and no decrease in the engine rotational speed N is detected is any of the following states (D) to (F): is there.
(D) A state in which the rotational speed N has become lower than the target rotational speed Nt because the load has once increased, but then the rotational speed has increased toward the target speed because the load has started to decrease.
(E) The rotational speed N has become lower than the target rotational speed Nt because the load has increased once. However, since there is no change in the load thereafter, the control by the governor works effectively, and the rotational speed increases toward the target speed. State to go.
(F) Although the load continues to increase after the rotational speed N becomes lower than the target rotational speed Nt because the load has once increased, the change in the increasing direction of the load is not abrupt. A state in which the rotation speed N increases to the target rotation speed Nt, effectively working.

  The states (A) to (F) are states in which the control by the governor is effective and the engine rotational speed can converge to the target rotational speed. In this embodiment, these states are detected. Control using the control gain correction coefficient at the time of load change, because it is determined that there is no change in the engine load, or even if the load fluctuates, no correction of the control gain at the time of load change is necessary. Does not perform gain correction.

  In this embodiment, it is determined whether the rotational speed of the engine tends to increase or decrease using the moving average value of the rotational speed. If configured in this way, a minute change in rotational speed is determined. Thus, it is possible to accurately determine whether the engine speed is increasing or decreasing.

  The load fluctuation control gain correction coefficient calculation means 8F is a means for calculating a load fluctuation control gain correction coefficient Cpl that is multiplied by the control gain reference value Kp in order to correct the control gain at the time of load fluctuation. The control gain correction coefficient calculation means 8F at the time of load fluctuation according to the present embodiment is used to calculate the operation amount when the load fluctuation determination means 8E determines that the engine load is fluctuating and the control gain needs to be corrected. In order to obtain the control gain to be used, a control gain correction coefficient Cpl at the time of load variation which is multiplied by the reference value Kp of the control gain is calculated for the rotational speed deviation dN. The calculation of the control gain correction coefficient Cpl at the time of load fluctuation is performed by using the map for calculating the control gain correction coefficient at the time of load fluctuation that gives the relationship between the rotation speed deviation dN and the appropriate value of the control gain correction coefficient Cpl at the time of load fluctuation. By searching against. A map for calculating the control gain correction coefficient at the time of load fluctuation is also experimentally created in advance and stored in the ROM.

  The control gain correction means 8G is a means for correcting the control gain reference value Kp to obtain the control gain used for the operation amount calculation. When the target speed changes, the control gain reference value Kp preset and stored in the ROM is used. A control gain reference value is corrected by performing a calculation Kp × Cpt × Cpl that multiplies the gain correction coefficient Cpt and the control gain correction coefficient Cpl at the time of load fluctuation to obtain a control gain used for calculation of the operation amount.

  3 and 4 are flowcharts showing algorithms of a governor control task to be executed by the microcomputer at a minute time interval in order to realize each means constituting the electronic governor shown in FIG. In this governor control task, first, in step 1 of FIG. 3, the moving average value Nv of the rotational speed calculated when this task was executed last time is stored as the previous moving average value Nv0. Next, at step 2, the engine rotational speed N is detected, and a moving average value of the rotational speed is newly calculated including the newly detected rotational speed.

  Next, the target rotational speed Nt set by the target speed setter 6 is read in step 3, and the process proceeds to step 4. In step 4, the target rotational speed Nt newly read in step 3 is compared with the previously read target rotational speed Nt0 to determine whether or not the target rotational speed has changed. As a result, if it is determined that the target rotational speed has changed, the process proceeds to step 5, and after calculating the target rotational speed fluctuation amount dNt = Nt−Nt0 as the target speed fluctuation quantity, the process proceeds to step 6. In step 6, the target speed fluctuation amount dNt is used to search the control gain correction coefficient calculation table Kpt_variable (dNt) for the target rotational speed fluctuation, and is set in advance to obtain the control gain used for the operation amount calculation. A control gain correction coefficient Cpt at the time of target rotational speed fluctuation is multiplied by the control gain reference value Kp.

Next, the routine proceeds to step 7 , where an operation Nt0 = Nt−dNt × Kat is performed by subtracting a numerical value obtained by multiplying the target speed fluctuation amount dNt by a preset damping coefficient Kat from the target rotational speed Nt read this time. The target rotational speed Nt0 (attenuated from the detected target rotational speed) is stored in the target speed storage means 21 as the previous target rotational speed. The attenuation coefficient Kat is set in advance to an appropriate value according to the characteristics of the engine that is the control target.

In the present embodiment, the target rotation speed Nt detected this time itself is not updated as the previous target rotation speed Nt0, but the attenuation coefficient Kat from the target rotation speed Nt detected this time to the target speed fluctuation amount dNt calculated this time. The value obtained by subtracting the target speed fluctuation amount dNt × Kat attenuated by multiplying by the number is updated as the previous target rotational speed Nt0 by maintaining that the target rotational speed has changed for a certain period of time. This is because the effect of correcting the gain is surely effective in controlling the actual rotational speed of the engine.

When implementing each means of configuring the electronic governor by causing the microprocessor to execute the governor control task at minute time intervals, the time from the previous task execution to the current task execution is extremely small, so this time detection When the target rotation speed Nt itself is updated as the previous target rotation speed Nt0 and the process of setting the control gain is performed, the time during which the control gain correction effect is effective becomes small. It is difficult to reliably reflect the effect of correcting the control gain on the control of the actual rotational speed of the engine. For example, if the governor control task is executed at an interval of 10 msec, when the target rotation speed Nt detected this time is updated as the previous target rotation speed Nt0, the time when 10 msec has elapsed after correcting the control gain. Then, it is determined that there is no change in the target rotation speed, and the control gain is not corrected. Here, if the rotational speed of the engine is, for example, 3000 rpm, the time required for one rotation of the engine is 20 msec, and one combustion cycle is 40 msec. The control effect of the rotational speed by the governor is Since it appears only after a stroke, assuming that the control gain correction effect lasts only for a time shorter than the time of one combustion cycle (40 msec), the control gain correction effect is reliably applied to the engine speed control. Difficult to reflect. When the governor control task is executed every 10 msec as in the above example, the ratio of the time during which the control gain correction effect lasts and the combustion time (correction effect duration / burning time) is 10/40 (= 1 / 4), the effect of correcting the control gain is effective only with a probability of 1/4. Actually, since it is desirable to maintain the effect of the control gain correction for 3 to 4 combustion cycles, it is necessary to extend the control time. In the present embodiment, the target rotational speed dt obtained by subtracting the target speed fluctuation amount dNt × Kat attenuated by multiplying the target speed fluctuation amount dNt calculated this time by the attenuation coefficient Kat from the target rotational speed Nt detected this time is the previous target rotational speed. By updating as the speed Nt0, the time during which the effect of the control gain correction is effective can be extended.

  If it is determined in step 4 that the newly read target rotational speed Nt is compared with the previously read target rotational speed Nt0, it is determined that the target rotational speed has not changed. The control gain correction coefficient Cpt during speed fluctuation is set to 1.

  After executing Step 7 or Step 8, the process proceeds to Step 9 in FIG. In step 9, a calculation for subtracting the target rotation speed Nt from the detected rotation speed N is performed to obtain a rotation speed deviation dN (= N−Nt).

  After performing Step 9, the process proceeds to Step 10 to determine whether the rotational speed deviation dN calculated in Step 9 is positive or negative (whether the actual rotational speed N is higher or lower than the target rotational speed Nt). . As described above, the rotational speed deviation dN becomes positive (the actual rotational speed N becomes higher than the target rotational speed Nt) when the target rotational speed is changed in the decreasing direction, because the load is reduced, the rotational speed deviation dN becomes the rotational speed. This is one of the three cases where an overshoot occurs and when the rotational speed increases excessively due to an excessive amount of operation in the control after the load increases and undershoot occurs. Also, the rotational speed deviation dN becomes negative (the actual rotational speed N becomes lower than the target rotational speed Nt). When the target rotational speed is changed in the increasing direction, the load increases and an undershoot occurs in the rotational speed. And when the rotational speed is excessively lowered due to an excessive amount of operation in the control after the load is reduced and overshoot occurs.

  If it is determined in step 10 that the rotational speed deviation dN is positive, the process proceeds to step 11 where the current moving average value Nv of the rotational speed calculated in step 2 is set to the previously calculated rotational speed. By comparing the moving average value Nv0 with the increase determination value Nv0 × ku obtained by multiplying the increase determination coefficient ku, it is determined whether or not the engine speed is higher than the increase determination value. When it is determined in step 11 that the moving average value Nv of the rotation speed calculated this time is larger than the increase determination value Nv0 × ku (when it is determined that the rotation speed deviation dN is positive and the rotation speed is increasing). In step S12, it is determined that the load has decreased and it is necessary to correct the control gain when the load fluctuates. The value Nv0 × ku obtained by multiplying the moving average value Nv0 of the previously calculated rotational speed by the increase determination coefficient ku is used as the increase determination value in order to make sure whether or not the engine rotation speed has increased. It is.

  When it is determined in step 10 that the rotational speed deviation dN is negative (the rotational speed N is lower than the target rotational speed Nt), the process proceeds to step 13 to move the rotational speed calculated in step 2 this time. By comparing the average value Nv with the decrease determination value Nv0 × kd obtained by multiplying the moving average value Nv0 of the previously calculated rotation speed by the decrease determination coefficient kd, the engine rotation speed is lower than the decrease determination value. It is determined whether or not. As a result, when it is determined that the moving average value Nv of the rotation speed calculated this time is lower than the decrease determination value Nv0 × kd (when it is determined that the rotation speed deviation dN is negative and the rotation speed is decreasing). In step S14, it is determined that the load is increased and the control gain correction at the time of load change is necessary. The value Nv0 × kd obtained by multiplying the moving average value Nv0 of the previously calculated rotational speed by the decrease determination coefficient kd is used as the decrease determination value in order to surely determine whether or not the engine rotational speed has decreased. It is.

  When it is determined in step 13 that the moving average value Nv of the rotational speed calculated this time is lower than the decrease determination value Nv0 × kd (when the conditions of steps 11 and 13 are not satisfied), the rotational speed deviation dN is negative. (The rotational speed is lower than the target rotational speed), the moving average value Nv of the rotational speed is higher than the decrease determination value Nv0 × kd, so the rotational speed of the engine approaches the target rotational speed. Therefore, it is determined in step 15 that correction of the control gain due to load fluctuation is unnecessary.

  When it is determined at step 12 that the engine load is decreasing and the control gain needs to be corrected, and when it is determined at step 14 that the load is increasing and the control gain needs to be corrected, step Then, the control gain correction coefficient Cpl during load fluctuation is calculated by searching the load fluctuation control gain correction coefficient calculation table Kp_variable (dN) for the rotational speed deviation dN. If it is determined in step 15 that correction of the control gain due to load fluctuation is unnecessary, the control gain correction coefficient Cpl during load fluctuation is set to 1 in step 17.

  After step 16 or 17 is executed, the process proceeds to step 18 where the operation amount is calculated by multiplying the reference value Kp of the proportional control gain by the control gain correction coefficient Cpt at the time of target rotational speed fluctuation and the control gain correction coefficient Cpl at the time of load fluctuation. The proportional control gain Kp (Kp × Cpl × Cpt) used for the calculation of is calculated. Next, the routine proceeds to step 19, where proportional control for converging the engine rotational speed to the target rotational speed is performed using the corrected proportional control gain, and this task is completed.

  In the case of the algorithm shown in FIGS. 3 and 4, the target speed change determining means 8A is constituted by step 4 and the target speed fluctuation amount calculating means 8B is constituted by step 5, respectively. Control gain correction coefficient calculation means 8C is configured. Further, the rotational speed average value calculating means 8D is configured by step 2, and the load fluctuation determining means 8E is configured by steps 10 to 15. Further, the control gain correction coefficient calculation means 8F at the time of load fluctuation is constituted by step 16, and the control gain correction means 8G is constituted by step 18. Further, the rotational speed deviation calculating means 7 is constituted by step 9.

  In order to perform control for converging the engine rotational speed to the target rotational speed, as in the above embodiment, only the proportional gain P among the three control gains of the PID is used, and the rotational speed deviation is set to (1 It is sufficient to calculate the amount of operation of the fuel adjustment unit by performing the proportional calculation of the first term on the right side of the equation), and to perform the proportional control (P control), but the proportional gain P and the integral gain I are Using the first and second terms of equation (1), or using the proportional gain P and differential gain D, the manipulated variables according to the first and third terms of equation (1). Or the manipulated variable may be calculated from the first to third terms of equation (1) using the proportional gain P, the integral gain I, and the differential gain D. In the above embodiment, the proportional gain P is set as an example. However, the integral gain and the differential gain can also be set in the same manner as in the above embodiment.

  The determination of whether or not the target rotational speed has changed in step 4 in FIG. 3 is performed by determining whether or not the target rotational speed Nt detected this time matches the previous target rotational speed Nt0. The target rotation speed may be determined to have changed when there is a difference of a certain value or more between the target rotation speed Nt detected this time and the target rotation speed Nt0 detected last time.

  In Step 7 of FIG. 3, the target rotational speed Nt0 attenuated by subtracting the target rotational speed variation dNt multiplied by the coefficient Kat from the target rotational speed Nt detected this time is the previously detected target rotational speed Nt0. Although it is set to the rotation speed, the effect of correcting the control gain by holding the change in the target rotation speed for a certain period of time is surely effective in controlling the actual rotation speed of the engine. In order to achieve this, it is only necessary to update (store) the target rotational speed obtained by attenuating the target rotational speed detected this time at a set ratio as the previous target rotational speed. It is not limited to what was shown in the embodiment. For example, the calculation of the attenuated target rotational speed Nt0 to be detected last time may be performed by a method of subtracting a constant value from the target rotational speed Nt detected this time, and the amount of attenuation is changed evenly by the designated number of times. It is also possible to use the method.

  When the attenuated target rotation speed Nt0 is obtained by the method of changing the attenuation amount evenly by the designated number of times, the target rotation speed change amount is dNt1, the attenuation execution number (task execution number) is n, and the specified attenuation number is By calculating Nt0 = Nt−dNt1 × (no−n) / no as no, the attenuation amount is decreased every time the number of attenuation executions n increases by 1, and the attenuation of Nt0 is performed when the attenuation is executed no times. The amount is 0 and Nt = Nt0.

  FIG. 5 shows an example of a change in the attenuated target rotational speed Nt0 in the case where the attenuation amount of the target rotational speed is uniformly changed by the designated number of times. In this example, Nt is set with no = 5. Attenuation is performed equally in five times, and the attenuation amount is set to 0 at the fifth time, so that Nt0 = Nt.

  In Step 10 of FIG. 4, it is determined whether or not the rotational speed deviation dN is positive. However, whether or not the rotational speed deviation dN is equal to or greater than a predetermined positive determination value and rotation. It is determined whether or not the speed deviation dN is equal to or less than a set negative determination value. If the rotation speed deviation dN is equal to or greater than a certain positive determination value, the process proceeds to step 11 where the rotation speed deviation dN is The process may proceed to step 13 when it is equal to or less than a certain negative determination value, and may proceed to step 15 when the rotational speed deviation dN is not equal to or greater than the certain positive determination value and not equal to or less than the certain negative determination value.

DESCRIPTION OF SYMBOLS 1 Electronic governor 2 Engine 3 Mixture supply amount adjustment part 5 Rotational speed detection means 6 Target speed setter 7 Rotational speed deviation calculation means 8 Control gain setting part 8A Target speed change determination means 8B Target speed fluctuation amount calculation means 8C Target speed fluctuation Time control gain correction coefficient calculation means 8D Rotational speed average value calculation means 8E Load fluctuation determination means 8F Load fluctuation time control gain correction coefficient calculation means 8G Control gain correction means 9 Operation amount calculation means 10 Operation signal output section

Claims (6)

An air-fuel mixture supply amount adjusting unit that adjusts the amount of fuel supplied to the engine, a control gain setting unit that sets a control gain, a rotation speed detecting means that detects the rotation speed of the engine, and a target rotation speed of the engine Rotational speed deviation calculating means for calculating a deviation from the rotational speed detected by the rotational speed detecting means as a rotational speed deviation, and calculating the rotational speed deviation using the control gain set by the control gain setting unit Operation amount calculation means for calculating the operation amount of the air-fuel mixture supply amount adjustment unit necessary for converging the engine rotation speed to the target rotation speed, and only the operation amount calculated by the operation amount calculation means In the engine electronic governor that performs control to converge the engine rotation speed to the target rotation speed by operating the air-fuel mixture supply amount adjustment unit,
The control gain setting unit includes a target speed fluctuation control gain correction factor determined according to the target rotational speed fluctuation amount and a load fluctuation time determined according to a rotational speed deviation caused when the engine load fluctuates. The engine is configured to determine a control gain used for the calculation of the manipulated variable by correcting a reference value of the set control gain using both of the control gain correction coefficient and the control gain correction coefficient. Electronic governor. Whether the load of the engine is fluctuating from the sign of the rotation speed deviation and the change tendency of the rotation speed detected by the rotation speed detecting means, and whether it is necessary to correct the control gain when the load fluctuates. Load variation determining means for determining whether or not
The control gain setting unit, when it is determined by the load fluctuation determination means that the load of the engine is fluctuating and it is necessary to correct the control gain, the control gain at the time of load fluctuation according to the rotational speed deviation Configured to determine a correction factor;
The electronic governor for an engine according to claim 1. An air-fuel mixture supply amount adjusting unit that adjusts the amount of fuel supplied to the engine, a control gain setting unit that sets a control gain, a rotation speed detecting means that detects the rotation speed of the engine, and a control gain that sets the control gain The amount of operation of the air-fuel mixture supply amount adjusting unit necessary for converging the engine speed to the target speed by calculating the deviation between the target speed and the actual speed of the engine as a gain set by the unit An operation amount calculation means for calculating the engine, and controls the engine speed to converge to the target rotation speed by operating the air-fuel mixture supply amount adjustment unit by the operation amount calculated by the operation amount calculation means. Electronic governor
The control gain setting unit is
Target speed change determination means for determining whether or not the target rotation speed has changed;
A target speed fluctuation amount calculating means for calculating a fluctuation amount of the target rotation speed when the target speed change determination means determines that the target rotation speed has changed;
When the target speed change determining means determines that the target rotational speed has changed, a target speed fluctuation gain correction coefficient that is multiplied by a reference value of the control gain to obtain a control gain used for the calculation of the manipulated variable is The target speed fluctuation gain correction coefficient is calculated when the target speed fluctuation amount is calculated by the target speed fluctuation amount calculation means and the target speed change determination means determines that the target rotation speed has not changed. A target speed fluctuation control gain correction coefficient computing means with a value of 1;
It is necessary to correct whether or not the load of the engine has fluctuated from the magnitude relationship between the rotation speed and the target rotation speed and the changing tendency of the rotation speed detected by the rotation speed detecting means, and to correct the control gain when the load fluctuates. Load variation determining means for determining whether or not there is,
The control gain for obtaining the control gain used for the calculation of the manipulated variable when it is determined by the load fluctuation determining means that the engine load is fluctuating and it is necessary to correct the control gain when the load fluctuates. When the load fluctuation control gain correction coefficient multiplied by the reference value is calculated for the rotational speed deviation, it is determined that the load of the engine is not fluctuated by the load fluctuation judging means, or the load fluctuates. Also, when it is determined that correction of the control gain is unnecessary, a control gain correction coefficient calculation unit for the load fluctuation control gain that sets the control gain correction coefficient for the load fluctuation to 1,
Control for obtaining a control gain used for calculating the manipulated variable by correcting the reference value of the control gain by multiplying the reference value of the control gain by the gain correction coefficient at the time of target speed fluctuation and the control gain correction coefficient at the time of load fluctuation Gain correction means;
With
An engine electronic governor characterized in that the control gain corrected by the control gain correcting means is used as a control gain used in the calculation of the manipulated variable. Target speed storage means for detecting the target rotation speed every minute time and storing the target rotation speed detected this time at a set rate and storing it as the previous target rotation speed is provided.
The target speed change determining means determines whether the target rotational speed has changed by comparing the target rotational speed detected this time with the previous target rotational speed stored in the target speed storage means. Configured,
The target speed fluctuation amount calculating means calculates a fluctuation amount of the target rotational speed by calculating a difference between the target rotational speed detected this time and the previous target rotational speed stored in the target speed storage means;
The electronic governor for an engine according to claim 3. The load fluctuation determination means is configured to detect the change in the increasing direction in the engine rotation speed detected by the rotation speed detection means in a state where the engine rotation speed is determined to be higher than the target rotation speed. Detected by the rotational speed detecting means in a state where it is determined that the engine load is decreasing and the control gain correction at the time of load fluctuation is necessary, and the engine rotational speed is determined to be lower than the target rotational speed. When a decrease in the engine rotation speed is detected, it is determined that the engine load is increasing and the control gain correction at the time of load fluctuation is necessary, and the engine rotation speed is higher than the target rotation speed. When it is determined that the engine speed is high and no change in the increasing direction is detected in the engine speed detected by the speed detecting means, and the engine speed is the target speed. When it is determined that the engine speed is determined to be lower than the speed and no change in the engine rotation speed detected by the rotation speed detection means is detected, the engine load is not changed or the load is changing. Is configured to determine that correction of the control gain at the time of load fluctuation is not necessary,
The engine electronic governor according to claim 3 or 4, wherein the electronic governor is used.   The load variation determining means determines whether the engine rotational speed is changing in the increasing direction or the decreasing direction from the change in the moving average value of the rotational speed detected by the rotational speed detecting means. The electronic governor for an engine according to claim 3, 4 or 5.

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